An Analysis of Variables
Affecting the Clearance of
Homicides: A Multistate Study
Charles Wellford
James Cronin
with the assistance of
Steve Brandl
Timonthy Bynum
Tom Eversen
Steve Galeria
October 1999
Justice Research and Statistics Association
777 North Capitol street, N.E.
Suite 801
Washington, D.C. 20002
202-842-9330
www.jrsa.org
Acknowledgments
This multistate research project was conducted by four state Statistical Analysis Centers: California (Steve Galeria, Director); Maryland (Charles Wellford, Director); Michigan (Tim Bynum, Director); and Wisconsin (Steve Grohmann). Charles Wellford, University of Maryland, served as Principal Investigator. James Cronin, University of Maryland, performed the data analyses. Site research was carried out in California by Roy V. Lewis, Sharon DeAngelis, and Debra Callahand; in Maryland, by Charles Wellford and James Cronin, with the assistance of Leanna Allen, Dawn Cecil, Daniel Lee, Ray Paternoster, and Andre Rosay; by Tim Bynum and Sean Varano in Michigan; and by Steve Brandl and Tom Eversen in Wisconsin.
We would like to thank the members of the project advisory group for their suggestions and ideas: Thomas Barnes, Charlotte-Mecklenburg Police Department; John Firman, International Association of Chiefs of Police; Lawrence Sherman, University of Maryland, and Richard Williams, Madison (WI) Police Department. We would also like to thank the following homicide detectives whose experience and expertise in homicide investigations were helpful during the planning stages of this project: Bud Campbell, Philadelphia Police Department; Errol Etting and Timothy Keel, Baltimore City Police Department; Larry Nodiff, Philadelphia Police Department; and Michael Sullivan, District of Columbia Metropolitan Police Department.
Paul White, Grant Manager at the Bureau of Justice Statistics, provided valuable information. Finally, Phyllis McDonald, our grant monitor at the National Institute of Justice, has lent us her knowledge and support throughout this project, for which we are extremely grateful.
The following staff of the Justice Research and Statistics Association made valuable contributions to this project: Kellie Dressler, Senior Program Manager, Office of Juvenile Justice and Delinquency Prevention (former JRSA Deputy Director); Nancy Michel, Editor; and Stan Orchowsky, Research Director.
Joan C. Weiss
Executive Director
| This project was supported by Grant No. 96-IJ-CX-0047 awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. Points of view in this document are those of the authors and do not neceessarily represent the official position or policies of the U.S. Department of Justice. |
Executive Summary Methodology Findings Conclusion Future References References Executive Summary
In recent years, the ability of law enforcement to make arrests in crimes would appear to have significantly diminished. This is especially true for homicide: from 1980 to 1996, the clearance rate for homicides decreased more than 7 %. While there has been a decrease in clearance rates nationally, some cities have high clearance rates for total crime and for homicides, and others have much lower rates than the average. Analysis of clearance rates from 1980 through 1994 shows that clearance rates in cities have remained very stable: those cities that are high in total clearance and high in homicide rates have remained consistently so throughout this period, as have cities which are high-low, low-high, and low-low. This stability suggests the existence of persistent factors that affect law enforcement agencies’ ability to clear homicide cases. The purpose of this study was to identify these factors by comparing the characteristics of solved and unsolved homicide cases.
This study examined 798 homicides that occurred in four large U.S. cities during 1994 and 1995. These cities were selected to maximize variation on homicide and total index crime clearance rates measured from 1980 through 1993. The cities include one that had relatively low homicide and total index crime clearance rates; another that had high homicide clearance rates and low total clearance rates; a third that had a high total clearance rate, but low homicide; and a fourth that had high total clearance and high homicide crime clearance.
Two data collection instruments were employed to provide information for the study. The Homicide Attribute Coding Instrument (HAC) provided a detailed description of the circumstances surrounding the homicide case, along with information regarding prior criminal records of victims and offenders, relationship between the victims and offenders, drug use by the offender or victim at the time of the incident, the number of eyewitnesses, and suspected motivation for the homicide.
The Investigative Instrument provided information related to the process used by homicide detectives to investigate the case. The Investigative Instrument provided information such as the status of the case, the number of detectives assigned to the case, what evidence was found at the crime scene and what types of checks and tests were performed on any evidence found, whether search warrants were issued, who was interviewed, and what information was obtained by following up on the initial stages of the investigation.
The data collected with these two instruments were gathered from a random sample of 200 homicide incidents in three cities and 198 in the fourth, for a total of 798 incidents. The cases in each city were selected so that the proportion of open and closed homicide cases in the sample matched that of the entire homicide caseload for those years for that city. This resulted in a total of 589 (74%) solved cases and 209 (26%) unsolved cases in the sample.
The data were collected by researchers from the Statistical Analysis Centers (SACs) in the states in which each city was located. Data collectors searched through the open and closed homicide case files in each city to locate relevant information.
A total of 215 factors related to the characteristics of the case and its investigation were examined to determine their relationship to the status of the case (solved or unsolved). The factors that were found in these preliminary bivariate analyses to be significantly related to the likelihood of the case being solved are listed below.
A case was more likely to be closed if the victim was not a drug user or buyer and had no criminal record. If the offender was Hispanic rather than black, the case was more likely to be solved. A case was more likely to be closed if the offender was not identified as a drug buyer.
Cases in which the victim was killed by the use of a rifle, knife, or personal weapon (hands or feet) were more likely to be solved than cases in which the victim was killed with a handgun. Furthermore, if the police identified the weapon used to kill the victim, the case was more likely to be solved.
The presence of drugs in a case had an effect on its closing. Cases in which drugs were a circumstance were less likely to be solved.
If the police did not identify the homicide as drug related, the homicide occurred in a private location, the weather was not bad, the crime scene was not identified as a drug market, or there was at least one witness, the case was more likely to be closed.
Motivation affected the closing of cases as follows: if the homicide involved preemption for an anticipated retaliatory attack, involved a conflict over money or property other than drugs, or the offender was defending him/herself, the case was more likely to be solved. If the homicide involved punishment for informing, the case was less likely to be closed.
The number of detectives assigned to a case, and their actions, had a significant effect on closing the case. A case was more likely to be solved if 3, 4, or 11 detectives were assigned to the case, compared to just one detective. The case was less likely to be solved if it took the detectives more than 30 minutes to arrive at the crime scene. If the detectives followed up on witness information, the case was more likely to be solved.
The homicide was less likely to be solved if the first officer on the scene did not notify the homicide unit, the medical examiner, or the crime lab, or if the officer did not attempt to locate witnesses. The case was less likely to be solved if the crime scene was not measured or if no weapon was found at the scene. If the crime scene itself was a residence, bar, or club rather than a public area, the case was more likely to be solved.
A case was more likely to be solved when witnesses were at the crime scene and provided valuable information, including the circumstances of death, the motivation for the homicide, an identification of the offender, an identification of the victim, or the location of the offender. When a neighborhood survey of the crime scene provided valuable information or the neighbors of the victim were interviewed, the crime was more likely to be solved. However, when friends of the victim were interviewed, the case was less likely to be solved.
When computer checks were conducted on a suspect or a gun, the case was more likely to be solved, but when computer checks were conducted on the victim or witnesses, the case was less likely to be solved.
Cases in which one of the detectives assigned was present at the postmortem examination were more likely to result in closure. When the medical examiner collected specimens, recovered a projectile, or prepared a body chart, the case was more likely to be solved.
The sources of information had an impact on the closing of cases. When police used surveillance in a case, the case was more likely to be solved. Additionally, cases in which confidential informants provided valuable information or witnesses came forward on their own were more likely to be closed.
When the variables discussed above were entered into a series of multivariate analyses, 15 variables remained which were significantly related to the probability of closing a case. These 15 variables were: 1) the offender was African American; 2) the offender was Hispanic; 3) a body chart of the victim was prepared; 4) a computer check on the decedent was conducted; 5) a computer check on the suspect was conducted; 6) a computer check on a witness was conducted; 7) a computer check on a gun was conducted; 8) the local Criminal Justice Information System (CJIS) was used for computer checks; 9) a witness at the crime scene provided valuable information; 10) friends and acquaintances of the victim were interviewed; 11) neighbors of the victim were interviewed; 12) three or more detectives were assigned to the case; 13) the location of the homicide was private; 14) an eyewitness observed the homicide; 15) the homicide was not drug-related.
These findings have important implications for the investigation of homicides. The study identified 51 characteristics of homicide events and investigative practices that were significantly associated with clearance. Of these, 37 were characteristics associated with police practices, with the remainder being characteristics associated with the homicide event. This indicates that law enforcement policies and procedures with regard to the investigation of homicides do make a difference in clearing cases. For example, it appears that the actions of the initially responding officer(s) at the crime scene are important. How quickly homicide detectives, evidence technicians, and medical examiners are notified and the time it takes them to respond to the scene are associated with clearance. The initial activities of the first responding officers, including securing the scene, identifying potential witnesses, preserving evidence, and initiating and participating in neighborhood surveys appear to be critical in solving homicide cases. The assignment of 3 or 4 detectives is optimal for clearing a case, but increasing the number is not efficient until one reaches very large numbers of detectives (11 or more).
The findings suggest the growing importance of computer checks of various types, particularly checks on guns, suspects, and victims. The results also suggest that defender and victim characteristics are not critical variables in understanding clearance, nor are many other characteristics of the case. While drug cases continue to be the most difficult for police to solve, the results show that the police can clear these cases given the proper allocation of resources.
Overall, these results suggest that practices and policies of law enforcement agencies can have a substantial impact on the clearance of homicide cases, and that clearance rates for homicide cases could be increased if law enforcement agencies improved investigation policies and procedures. There are few homicide cases that given the right initial response, the right timing, and the right dedication of resources cannot be solved.
Introduction
In recent years, the number of arrests made in crimes known to police has significantly diminished in the United States. The Uniform Crime Reports (UCR), which indicate the number of specific crime types reported to police and the number of arrests made for those crimes, have shown a decline in clearance rates since the 1960s. Additionally, various reports from individual law enforcement agencies have also indicated a decline, especially for one of the most serious crimes, the crime of homicide.
UCR clearance rates indicate the rate of arrests made for a particular type of crime. For example, the homicide clearance rate is determined by dividing the number of homicides reported in a year by the number of arrests made for those homicides. However, for homicides, the number of murder/suicides and the number of self-defense homicides are also included with the number of arrests when determining the clearance rate. In other words, a case is considered cleared or closed if it was determined to be in self-defense or the offender committed suicide at the scene.
Figure 1 shows the national clearance rate for homicide from 1961 to 1996. As the figure indicates, the homicide clearance rate declined from 94% in 1961 to 67% in 1996. That means an arrest occurred for 94% of the homicides in 1961 and only 67% of the homicides in 1996. While there are many reasons to believe clearance rates are not a dependable measure of police performance (e.g., the arrest of a suspect does not necessarily mean the suspect actually committed the crime), clearance rates can and have been used to indicate the arrest of the most probable crime suspect.
Figure 1 Percent of U.S. Homicides Cleared by Arrest, 1961-1996
The arrest of a suspect is one of the most important events in the criminal justice system, for without an arrest, none of the accepted forms of punishment can be applied. According to deterrence theory (Beccaria, 1764/1963) a punishment must be applied with certainty, severity, and celerity to prevent an offender from committing future offenses (specific deterrence), as well as to prevent others who witness the results of the punishment from engaging in criminal behavior (general deterrence). Although traditionally most of the emphasis has been placed on severity, criminologists have long considered certainty and celerity to be the more important aspects of deterrence (Beccaria, 1764/1963). Therefore, a decrease in clearance rates (low certainty) signals an inability of the criminal justice system to achieve one of its primary goals–the reduction of future crime, both specific and general. Similarly, incapacitation, rehabilitation, retribution, or any other aim of punishment cannot be achieved without an arrest. Clearance rates can also affect citizens’ perception and fear of crime, in addition to reflecting the criminal justice system’s ability to impose punishments on offenders.
While clearance rates have decreased nationally, the clearance rates of individual jurisdictions show variation. Table 1 represents the 1994 homicide clearance rates for the 20 largest cities in the United States for which UCR data are available, excluding New York City. The table depicts the level–high, medium, or low–of both the total clearance rate and the homicide clearance rate in a 3x3 matrix. The levels (high, medium, and low) are determined by breaking the 20 cities into three equal percentiles on homicide and total clearance rate. Some cities are uniformly high, uniformly medium, uniformly low, or varied with regard to total clearance and homicide clearance rates. Some cities have high clearance rates for total crimes and homicides. Others have much lower than average clearance rates. The 20 cities are spread throughout the matrix. Our preliminary analysis for the period from 1980 through 1994 demonstrated that the clearance rates in these cities have remained amazingly stable over time and in relation to each other. This is especially true for cities at the high and low ends of the classification. While a few shifts in the relative level of clearance rates have occurred for some cities (e.g., San Francisco), generally cities with high clearance rates have had high clearance rates from 1980 to 1994 and cities with low clearance rates have had low clearance rates throughout that period. This was true for both homicide and total clearance rates taken together and taken separately, indicating that there are variables affecting clearance rates in these cities that are constant. Identifying these variables related to high levels of clearance could help improve police practices and the ability of departments to clear serious crimes.
Table 1 Homicide and Total Clearance Rate Levels, 1994, for 20 of the Largest Cities in the United States
| Total Clearance Level | Homicide Clearance
Level |
||
| High | Medium | Low | |
| High | City Aa Austin Dallas |
Jacksonville Philadelphia San Jose |
City C Boston |
| Medium | El Paso | Memphis Phoenix Seattle |
San Diego Washington, D.C. |
| Low | City D | Columbus Houston |
City B San Antonio San Francisco |
a Cities A, B, C, and D are the cities selected for study.
This study addresses the issue of clearance rates with the expectation that by understanding what accounts for cities having high clearance rates for homicide, we will be able to prescribe changes that other departments could use to improve their rate of homicide clearance. We focused on homicide because it is a type of crime to which substantial police resources are devoted and one that greatly affects the public’s confidence in law enforcement’s ability to deter crime. Large cities were used because of the substantial contribution they make to the total homicide problem in the United States. In 1993, for example, 50.3% of the homicides in the United States occurred in 62 of the largest cities (Maguire & Pastore, 1995). Finally, by closely examining the way clearance rates are constructed in different cities, we hope to offer guidance on the extent to which clearance rates can function as a measure of police performance in dealing with the most serious crime reported to police.
Prior Research
Surprisingly, very little research has been conducted on the determinants of clearance rates for any type of crime, including homicide. Our review of the existing literature found no comparative studies and no systematic attempt to understand the determinants of clearance. While there has been some speculation on what affects clearance rates, this speculation has not involved systematic research. The International Association of Chiefs of Police Murder Summit (1995) and studies by Riedel and Rinehart (1994) and Cardarelli and Cavanaugh (1992) have demonstrated the decline in homicide clearance, have offered various reasons for the decline, and have identified certain methodological problems in this research. The suggested reasons for the decline in homicide clearance can be categorized as follows:
These suggestions provide interesting anecdotal hypotheses that might explain changes in homicide clearance, but no one has subjected these or other possible explanations to systematic research.
In part, the absence of systematic research has been, as Maxwell (1989) has observed, due to problems in the national data on homicides. The primary source of homicide data is the supplemental homicide reports (SHR) filed with the Federal Bureau of Investigation (FBI). These reports are quite useful for basic descriptions of homicides, including details such as race, ethnicity, and gender of victim and offender; number of victims and offenders in the incident; weapons used; circumstances of the homicide; and relationship between victim and offender. However, the SHR do not indicate how the homicide was cleared or whether it was cleared. UCR data also do not provide detailed information on the nature of the offense or, more importantly, on the nature of the investigation. Therefore, they offer little as a source of data for understanding the clearance process.
The absence of research on the homicide investigation process is not surprising when one considers the general absence of attention by researchers to police investigations other than those conducted by patrol officers. The works of Greenwood, Chaiken, and Petersilia on detectives (1977), Skolnick on rape investigations (1966), Forst on arrest convictability (1982), and Eck (1992) on investigation are the most widely cited studies of nonpatrol investigation practices. Greenwood’s work was focused more on outcomes than it was on the variations in strategies and their impact on outcomes. It is widely thought to question whether the resources devoted to detective functions are justified. Skolnick focused more on the role the victim plays in determining the level of investigation. Forst was most concerned with developing a measure of patrol performance that relates to the subsequent conviction of arrested offenders. Eck focused more on the conceptualization of the investigation than on analysis of the models he developed.
In general, criminologists have paid more attention to patrol functions than the investigative process. For example, in a recent compendium of police research (Tonry and Morris, 1992), not one mention is made of studies of detectives or other police investigations (except those in internal affairs). Given the seriousness of cases referred for investigation, especially homicide cases, our research on homicide units and the cases they handle is important and should have an impact on the resources allocated to homicide units in all medium and large police departments.
Methodology
Using data provided to us by the FBI, we constructed a data set for 170 cities consisting of their levels of total crime and homicide, the demographic characteristics of the city, and the number of homicides and other crimes cleared by an arrest for 1980, 1985, 1990, 1991, 1992, 1993, and 1994. In addition to creating and conducting preliminary analyses of these data, we focused on 20 of the largest cities, looking for variations in their rates of clearance, changes in clearance rates through this period, and levels of homicide. As noted above, these analyses demonstrated clearance rate levels for most of these cities are relatively stable from the period 1980 through 1994, although the cities varied considerably in their rates of clearance of homicide. For that reason, our basic study design is multisite, selecting four cities that have relatively stable patterns of clearance and high levels of homicide. Only four cities were chosen because of limited resources. The four cities are not identified because of an agreement to maintain their anonymity.
City A’s Police Department has consistently had high rates of clearance for homicides and for total crimes relative to the other departments. City B has had a low rate for each of these crime categories. City C has had a high rate of clearance for total crimes but a low homicide clearance rate, and City D has had a high homicide clearance rate but a low total crime clearance rate. These four cities were among those of the largest cities in the United States with the highest homicide rates in 1994. Figure 2 shows the homicide clearance rate for these four cities for the period 1980–93. These four cities have had high homicide rates and consistently different clearance levels throughout this 14-year period.
Figure 2 Percent of Homicides Cleared by Arrest, 1980-1993
Instruments
Three instruments were employed to provide information for this study. The instruments describe the circumstances surrounding the homicide case, the investigation process, and the organizational structure of the departments.
The Homicide Attribute Coding Instrument (HAC) supplies a detailed description of each homicide case. It provides information concerning prior records of the victim and offender, relationship between victim and offender, drug use by the offender or victim at the time of the incident, the number of eyewitnesses, and motivation for the homicide. Examples of motivations for the homicide include rivalry over a lover; conflict over drugs, drug paraphernalia, or drug territory; commission of a crime; and conflicts not involving drug use. The purpose of the HAC instrument is to describe the circumstances surrounding the homicide.
The Investigative Instrument arose from a focus group consisting of police researchers and experienced homicide investigators from three different departments. The group helped identify key aspects of the investigation that should be included in the instrument. The Investigative Instrument provides information such as the status of case; the number of detectives assigned to the case; evidence found at the scene; whether search warrants were issued; interviews with witnesses, family, friends, neighbors, hospital staff, and the medical examiner; and details gathered from following up on information acquired during initial stages of the investigation. The Investigative Instrument describes the events that occurred during the investigation.
The last instrument provides an organizational profile of the four homicide departments. The Organizational Instrument characterizes the level of resources, personnel, training, and management each department devoted to homicide investigations during the last 10 years. This instrument also provides information concerning the dynamics of each department during the past 10 years.
Data Collection
The data collected from the HAC Instrument and the Investigative Instrument were gathered from a random sample of 200 homicide incidents in each city, for a total of 800 incidents. The homicides occurred during the years 1994 and 1995. However, the cases may have been solved after those years since the data were collected from September 1997 to January 1998. The total number of open and closed cases was known before the sampling process was begun. It was not known, however, which individual cases were open and closed. Therefore, a random sample was used to approximate the proportion of open and closed cases for each city.
The data for the HAC and Investigative Instruments were collected from the homicide departments’ case files. Data collectors searched through the open and closed homicide files to locate relevant information. In departments with well-organized files, the HAC and Investigative Instruments both took approximately an hour and fifteen minutes to complete; in the less organized files, the two instruments took up to two and a half hours to complete.
Some homicide cases involve more than one victim. Cases with multiple homicides were regarded as one incident. Victim information was collected for all victims in multiple homicide cases and entered in the database.
The Organizational Instrument was mailed out to the site researchers in each state. The site researchers were responsible for having the department in their city fill out the instrument. Some departments could not fill out all the information due to the organizational structure of their departments. For example, in City C, everything is done on a divisional level, not a unit level. Therefore, some information, such as the budget, overtime spending, and number of personnel, is known only at the departmental level, and not for the homicide units. Additionally, one department did not return its Organizational Instrument and another department was not comfortable giving out the information asked in the instrument. Therefore, an analysis of the Organizational Instrument could not be performed.
Findings
The findings consist of four sections. The first two sections are descriptive in nature: the first section describes the homicides and the second describes the investigative process. The third section discusses variables associated with solving a case. Logistical regression analysis, with clearance as the dependent variable, is used to determine the estimated impact various variables had on clearing a case. The final section presents logistical regression models using independent variables that have a significant effect on solving a case.
Homicide Case Analysis
Detailed data were collected on 798 homicides in City A, City B, City C, and City D. The sample contains 200 homicide cases from each city, except for City C, which submitted 198 cases. This section consists of three parts. Part one discusses general circumstances of the homicide, part two contains victim information, and the final part discusses information about the offender.
General Circumstances
A total of 589 (74%) solved cases and 209 (26%) unsolved cases are in our sample. Of the unsolved cases, 44 are still active with the homicide unit, 87 have been turned over to the "cold case" squad, and 78 are inactive. The "cold case" squad attempts to solve cases that the regular homicide unit has been unable to solve. Inactive cases are open cases that no one is currently attempting to solve. These cases could become active again if new information is discovered.
Of the cases active with the homicide unit, the mean time since the case opened is 35.1 months (1,067 days). The mean time since a case has been opened for cases turned over to the cold case squad is 35.4 months (1,078 days). For inactive cases, the mean time since the case opened is 36.4 months (1,105 days). The average unsolved case in our study has been open for approximately 3 years. Of the closed cases in our study, 93.2% were solved within 1 year and 50% were solved within a week. Therefore, if a case is not solved within a year, the chances of it ever being solved are low.
Table 2 lists motivations for the homicide for all cases, closed cases, and open cases. The motivations, which were classified by the data collectors who read the homicide files, are based on the percent of known motives. The motivations can and do overlap in some cases. The predominate reason for committing the homicide for all cases was "other conflict" (43.0%). "Other conflict" involves an argument between the victim and offender that does not involve money or drugs. The second largest motivation for the homicide was drug related (26.4%). Some of the drug-related motives are failure to pay a drug debt, robbery during a drug deal, and conflict over drug territory. The third greatest motivation for the homicide was retaliation (22.7%). This was followed by taking of property (18.1%), conflict over money (15.7%), self-defense (11.5%), victim killed while committing a crime (11.1%), victim was a bystander who was killed inadvertently (7.8%), rivalry over a lover (7.2%), killed by an authority figure (5.3%), and victim randomly selected from a particular social group (4.1%). Killed by an authority figure refers to being killed by a parent or guardian.
Table 2 Motivations for the Homicide for All Cases
| Motivation | Percent
of Cases |
||||||
| City A | City B | City C | City D | All Cities | |||
| Motivation know to police | 82.4 | 87.3 | 79.2 | 87.5 | 84.1 | ||
| Single Motivation for homicide | 61.6 | 40.1 | 64.1 | 52.6 | 54.3 | ||
| Retaliation Drug related Taking of property Victim killed while committing a crime Offender defending themselves Victim was a bystander killed inadvertently Conflict over money Rivalry over a lover Victim randomly selected from a particular social group Killed by an authority figure Other conflict (not money or drugs) |
24.3 33.4 16.6 20.1 9.9 9.9 5.3 7.6 0.0 4.0 33.6 |
29.4 30.0 21.2 12.1 15.0 6.3 23.8 9.4 1.3 4.3 50.6 |
20.1 16.0 14.7 5.6 4.8 7.0 14.7 4.1 14.6 2.0 42.7 |
16.8 26.5 20.0 6.5 15.5 8.4 16.8 7.1 0.6 10.5 43.2 |
22.7 26.4 18.1 11.1 11.5 7.8 15.7 7.2 4.1 5.3 43.0 |
||
| Combination of motives | 38.4 | 59.9 | 35.9 | 47.4 | 45.7 | ||
| Motive unknown to police | 17.6 | 12.7 | 20.8 | 12.5 | 15.9 | ||
Motivations for the Homicide for Closed Cases
| Motivation | Percent
of Cases |
||||||
| City A | City B | City C | City D | All Cities | |||
| Motivation know to police | 0.3 | 1.9 | 84.4 | 92.4 | 89.9 | ||
| Single Motivation for homicide | 58.8 | 36.0 | 61.4 | 51.0 | 51.6 | ||
| Retaliation Drug related Taking of property Victim killed while committing a crime Offender defending themselves Victim was a bystander killed inadvertently Conflict over money Rivalry over a lover Victim randomly selected from a particular social group Killed by an authority figure Other conflict (not money or drugs) |
22.8 28.2 15.2 22.8 10.9 10.9 6.3 7.2 0.0 5.2 35.4 |
26.4 25.6 18.2 9.4 18.1 7.5 24.8 9.1 1.6 5.9 56.9 |
17.1 13.4 17.0 6.7 4.8 6.7 16.2 4.8 14.3 3.0 45.8 |
16.9 24.0 20.0 7.6 16.2 7.8 18.3 7.1 0.7 12.0 44.4 |
20.9 23.0 17.7 11.6 12.9 8.1 16.7 7.1 3.8 6.9 45.8 |
||
| Combination of motives | 41.2 | 64.0 | 38.6 | 49.0 | 48.4 | ||
| Motive unknown to police | 9.7 | 8.1 | 15.6 | 7.6 | 10.1 | ||
Motivations for the Homicide for Open Cases
| Motivation | Percent
of Cases |
||||||
| City A | City B | City C | City D | All Cities | |||
| Motivation know to police | 61.1 | 77.0 | 67.7 | 60.0 | 67.6 | ||
| Single Motivation for homicide | 72.7 | 51.1 | 71.4 | 66.7 | 64.3 | ||
| Retaliation Drug related Taking of property Victim killed while committing a crime Offender defending themselves Victim was a bystander killed inadvertently Conflict over money Rivalry over a lover Victim randomly selected from a particular social group Killed by an authority figure Other conflict (not money or drugs) |
28.0 60.7 20.4 13.0 4.6 4.6 0.0 9.3 0.0 0.0 23.9 |
38.5 43.7 27.9 18.0 5.2 2.5 20.5 10.3 0.0 0.0 30.8 |
28.5 23.3 9.7 3.2 5.2 7.8 10.6 2.6 15.5 0.0 34.2 |
15.5 53.8 20.0 0.0 7.6 15.5 0.0 7.6 0.0 0.0 3.7 |
30.4 41.0 19.3 9.7 5.4 6.2 10.8 7.1 5.4 0.0 30.6 |
||
| Combination of motives | 27.3 | 49.9 | 28.6 | 33.3 | 35.7 | ||
| Motive unknown to police | 38.9 | 23.0 | 32.3 | 40.0 | 32.4 | ||
The motivations for the closed cases were "other conflict" (45.8%), drug related (23.0%), retaliation (20.9%), taking of property (17.7%), conflict over money (16.7%), self-defense (12.9%), victim killed while committing a crime (11.6%), victim was a bystander killed inadvertently (8.1%), rivalry over a lover (7.1%), killed by an authority figure (6.9%), and victim randomly selected from particular social group (3.8%). A motive was unknown by the police in 10.1% of the closed cases. Of those cases, 66% of the time the victim and offender knew each other before the homicide incident.
The motivations for open cases were in a slightly different order than for closed cases. The main motivation was drug related (41.0%). This was followed by "other conflict" (30.6%) and retaliation (30.4%). Next was taking of property (19.3%), conflict over money (10.8%), victim killed while committing a crime (9.7%), rivalry over a lover (7.1%), victim was a bystander killed inadvertently (6.2%), self-defense (5.4%), and victim randomly selected from a particular social group (5.4%). There were no open cases with the motivation killed by an authority figure.
Table 2 also lists motives by city. Some difference in motivation across cities can be seen. Homicides in City B are more likely to involve more than one motive than homicides in the other three cities. Homicides in City C are less likely to be drug related but more likely to involve randomly selecting a victim from a particular social group. Homicides in City A are less likely to involve a conflict over money or an "other conflict" compared to the other cities, but more likely to involve the victim getting killed while committing a crime.
Table 3 lists the primary cause of death for all homicides, closed homicides, and open homicides. The majority of homicides involved being shot by a handgun (65.7%). This was distantly followed by being stabbed with a knife or other instrument (11.0%), being shot with other than a handgun (9.5%), and other causes of death (13.7%).
Table 3 Primary Cause of Death for All Cases
| Cause of Death | Percent of Cases |
||||
| City A | City B | City C | City D | All Cities | |
| Shot with a handgun Shot with other than a handgun Stabbed Other Missing |
75.5 3.0 9.5 12.0 0.0 |
61.8 19.0 8.0 11.0 0.5 |
64.1 11.6 12.6 11.6 0.0 |
61.5 4.5 14.0 20.0 0.0 |
65.7 9.5 11.0 13.7 0.1 |
Primary Cause of Death for Closed Cases
| Cause of Death | Percent of Cases |
||||
| City A | City B | City C | City D | All Cities | |
| Shot with a handgun Shot with other than a handgun Stabbed Other Missing |
74.5 2.8 10.3 12.4 0.0 |
62.6 17.3 7.9 12.2 0.0 |
62.2 11.9 13.3 12.6 0.0 |
61.2 3.5 15.9 19.4 0.0 |
65.0 8.5 12.1 14.5 0.0 |
Primary Cause of Death for Open Cases
| Cause of Death | Percent of Cases |
||||
| City A | City B | City C | City D | All Cities | |
| Shot with a handgun Shot with other than a handgun Stabbed Other Missing |
78.2 3.6 7.3 10.9 0.0 |
59.0 23.0 8.2 9.8 1.6 |
68.3 11.1 11.1 9.5 0.0 |
63.3 10.0 3.3 23.2 0.0 |
67.5 12.4 4.3 11.5 0.5 |
The primary cause of death for each city is also listed in Table 3. Three noticeable differences between cities can be seen. The primary cause of death is more likely to be a handgun in City A than in the other cities. Being shot with other than a handgun is more likely to occur in City B than in the other three cities. And homicides in City D are more likely to involve "other" (not shot or stabbed) causes of death.
Table 4 lists characteristics surrounding the homicides. Drugs were found at the scene for 16.2% of the homicides and alcohol was found at 16.5% of the homicide scenes. The homicide scenes were described as "drug market areas" in 27.9% of the cases. The police located at least one eyewitness for 61.5% of the homicides. The homicide occurred in a vehicle for 13.8% of the homicides. The taking or attempting to take property was involved in 18% of the homicides. The victim was killed while committing a crime 11.0% of the time.
Table 4 Characteristics of the Homicide
| Characteristics | Percent of Cases |
||||
| City A | City B | City C | City D | All Cities | |
| Eyewitness found at scene Scene identified as a "drug market" Involved gang or drug organization member involved taking or attempting to take property Alcohol found at scene Drugs found at scene Occurred in a vehicle Victim killed while committing a crime Victim killed by an authority figure (e.g., parent, babysitter) Victim or offender involved in prostitution Involved sexual assault |
66.5 10.0 6.0 16.5 7.0 15.0 8.5 20.0 2.5 1.0 1.5 |
58.5 19.5 26.0 21.0 25.0 21.5 17.5 12.0 3.0 4.0 1.5 |
76.3 68.2 51.0 14.6 22.7 9.1 16.7 5.6 2.0 1.5 1.5 |
45.0 14.5 16.5 20.0 11.5 19.0 12.5 6.5 6.0 3.0 2.5 |
61.5 27.9 24.8 18.0 16.5 16.2 13.8 11.0 3.4 2.4 1.8 |
Table 4 also reveals differences in homicide characteristics between cities. In City C, the homicide scene was identified as a drug market more often than in the other three cities. Additionally, the homicides in City C involved more gang or drug organization members.
Victim Information
Table 5 contains the number of victims and decedents in each homicide incident. The majority of the homicides (95.7%) involved one decedent. Two decedents were found in 3.9% of the cases and three deaths occurred in 0.4% (n = 3) of the cases. However, 75.3% of the cases involved one victim and 24.7% of the cases involved two or more victims. Therefore, a quarter of homicide incidents involved two or more victims, but less than 5% of homicide incidents involved two or more deaths.
Table 5 Number of Victims per Homicide Incident
| Member | Victims |
||||
| City A | City B | City C | City D | All Cities | |
| 1 | 78.0 (156) |
73.5 (147) |
68.7 (136) |
81.0 (162) |
75.3 (601) |
| 2 | 12.5 (25) |
15.0 (30) |
20.2 (40) |
11.0 (22) |
14.7 (117) |
| 3 or more | 9.5 (19) |
11.0 (22) |
11.1 (22) |
8.0 (16) |
9.9 (79) |
| Unknown | 0.0 (--) |
0.5 (1) |
0.0 (--) |
0.0 (--) |
0.1 (1) |
Number of Decedents per Homicide Incident
| Member | Decedents |
||||
| City A | City B | City C | City D | All Cities | |
| 1 | 96.0 (192) |
92.0 (184) |
97.5 (193) |
97.5 (195) |
95.7 (764) |
| 2 | 4.0 (8) |
6.5 (13) |
2.5 (5) |
2.5 (5) |
3.9 (31) |
| 3 or more | 0.0 (--) |
1.5 (3) |
0.0 (--) |
0.0 (--) |
0.4 (3) |
| Unknown | 0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
Table 6 Victim Characteristics (Age, Race, and Sex)
| Age Group (years) |
Male |
Female |
All Cases |
||||||||
| White | African American | Hispanic | Other | Missing | White | African American | Hispanic | Other | Missing | ||
| 0-14 | 0.2 (2) |
1.8 (14) |
0.5 (4) |
0.0 (--) |
0.0 (--) |
0.1 (1) |
1.3 (11) |
0.0 (--) |
0.0 (--) |
0.1 (1) |
4.1 (33) |
| 15-24 | 1.1 (9) |
22.8 (182) |
7.4 (59) |
0.6 (5) |
0.2 (2) |
0.4 (3) |
2.3 (18) |
0.5 (4) |
0.2 (2) |
0.1 (1) |
35.7 (285) |
| 25-34 | 2.6 (21) |
19.7 (157) |
3.5 (28) |
0.2 (2) |
0.4 (3) |
0.0 (--) |
3.1 (25) |
0.1 (1) |
0.0 (--) |
0.0 (--) |
29.7 (237) |
| 35-44 | 2.6 (21) |
10.0 (80) |
1.9 (15) |
0.5 (4) |
0.0 (--) |
0.4 (3) |
2.1 (17) |
0.4 (3) |
0.2 (2) |
0.0 (--) |
18.2 (145) |
| 45-64 | 1.1 (9) |
4.1 (33) |
0.8 (0.6) |
1.2 (2) |
0.0 (--) |
0.2 (2) |
0.4 (3) |
0.1 (1) |
0.0 (--) |
0.0 (--) |
7.0 (56) |
| 65+ | 0.8 (6) |
1.1 (9) |
0.0 (--) |
0.1 (1) |
0.0 (--) |
0.6 (5) |
0.1 (1) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
2.8 (22) |
| Missing | 0.2 (2) |
0.9 (7) |
0.4 (3) |
0.0 (--) |
0.0 (--) |
0.1 (1) |
0.6 (5) |
0.2 (2) |
0.0 (--) |
0.0 (--) |
2.5 (20) |
| Total | 8.8 (70) |
60.4 (482) |
14.4 (115) |
1.8 (14) |
0.6 (5) |
1.9 (15) |
10.0 (80) |
1.3 (11) |
0.5 (4) |
0.2 (2) |
100.0 (798) |
The persons with the highest risk of being a homicide victim in our sample were young, black males. Table 6 presents the homicide rate by age, sex, and race. The victim was 24 years of age or under in 39.8% of the cases. In 70.4% of the cases the victim was African American and 86.0% of the victims were male.
Alcohol was being used by 21.5% of the decedents at the time of their death, and 15.1% of the decedents were using drugs. Police identified 19.8% of the decedents as drug dealers and 13.6% of the decedents as drug buyers. The decedents were killed while buying drugs in 3.6% of the cases and killed while selling drugs in 6% of the cases.
Criminal record searches revealed 29.8% of the decedents had a prior record for drugs, 31.9% had a prior record for violent crimes, and 33.3% had a prior record for property crimes. In all, 48% of decedents had some type of prior record. At the time of the homicide, 15% of the decedents were in possession of a weapon.
Offender Information
The majority of homicides involved a lone offender. Two-offender homicides occurred in only 9.3% of the cases. Young, black males represent the majority of offenders in our sample. Table 7 displays the offenders’ age, sex, and race. The offenders were 24 years old or younger in 53.7% of the cases. In 93.5% of the cases the offender was a male and in 74.8% of the cases the offender was an African American.
Police officers account for 1% (n = 8) of the "offenders" in our sample. In 7 of the 8 police officer homicides in our sample, the officer was acting in the line of duty. In the eighth case, the officer was off duty and the homicide was not justifiable.
Alcohol was being used by 15.9% of the offenders at the time of the incident and 8.6% of the offenders were on drugs when they killed the victim. Police identified 2.5% of the offenders as drug buyers and 3.5% of them as drug sellers. A criminal records search revealed 24.8% of offenders had a prior record for a drug offense, 33.6% had previously committed a violent crime, and 31.5% had a prior record for a property crime. In all, some type of prior record was found for 45.1% of the offenders.
Table 7 Offender characteristics (Age, Race, and Sex)
| Age Group (years) |
Male |
Female |
All Casesa |
||||||||
| White | African American | Hispanic | Other | Missing | White | African American | Hispanic | Other | Missing | ||
| 0-14 | 0.0 (--) |
0.6 (4) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.3 (2) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.9 (6) |
| 15-24 | 1.3 (9) |
38.1 (257) |
9.8 (66) |
0.7 (5) |
0.4 (3) |
0.6 (4) |
1.8 (12) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
52.8 (356) |
| 25-34 | 1.9 (13) |
14.4 (97) |
2.7 (18) |
0.4 (3) |
0.3 (2) |
0.0 (--) |
2.1 (14) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
21.8 (147) |
| 35-44 | 0.9 (6) |
6.4 (43) |
0.7 (5) |
0.0 (--) |
0.0 (--) |
0.1 (1) |
0.9 (6) |
0.1 (1) |
0.0 (--) |
0.0 (--) |
9.2 (62) |
| 45-64 | 0.7 (5) |
2.5 (17) |
0.7 (5) |
0.4 (3) |
0.1 (1) |
0.0 (--) |
0.4 (3) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
4.9 (33) |
| 65+ | 0.1 (1) |
0.3 (2) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.4 (3) |
| Missing | 0.3 (2) |
7.1 (48) |
2.5 (17) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
0.0 (--) |
9.9 (67) |
| Total | 5.3 (36) |
69.3 (468) |
16.4 (111) |
1.6 (11) |
0.9 (6) |
0.7 (5) |
5.5 (37) |
0.1 (--) |
0.0 (--) |
0.0 (--) |
100 (675) |
a There are 123 cases for which the race, gender, and age of the offender are unknown.
Table 8 Relationship Between Victim and Offender for All Cases
| Relationship | Percent
of Cases |
|||||
| City A | City B | City C | City D | All Cities | ||
| Victim knew offender | 46.0 | 55.0 | 45.5 | 66.0 | 53.1 | |
| Member of the same family Romantic relationship Friendship/Circumstance |
4.0 6.5 24.5 |
13.0 7.0 31.5 |
3.5 3.5 38.4 |
10.5 8.0 42.5 |
7.8 6.3 34.2 |
|
| Strangers | 28.0 | 18.0 | 28.3 | 20.0 | 23.6 | |
| Relationship unknown | 26.0 | 27.0 | 26.3 | 14.0 | 23.3 | |
Relationship Between Victim and Offender for Closed Cases
| Relationship | Percent
of Cases |
|||||
| City A | City B | City C | City D | All Cities | ||
| Victim knew offender | 62.1 | 73.4 | 59.3 | 75.9 | 68.1 | |
| Member of the same family Romantic relationship Friendship/Circumstance |
5.5 9.0 33.1 |
18.0 10.1 41.7 |
5.2 4.4 50.4 |
12.4 9.4 48.8 |
10.4 8.3 43.6 |
|
| Strangers | 37.2 | 22.3 | 39.3 | 23.5 | 30.2 | |
| Relationship unknown | 0.7 | 4.3 | 1.5 | 0.6 | 1.7 | |
Relationship Between Victim and Offender for Open Cases
| Relationship | Percent
of Cases |
|||||
| City A | City B | City C | City D | All Cities | ||
| Victim knew offender | 3.6 | 13.1 | 15.9 | 10.0 | 11.0 | |
| Member of the same family Romantic relationship Friendship/Circumstance |
0.0 0.0 1.8 |
1.6 0.0 8.2 |
0.0 1.6 12.7 |
0.0 0.0 6.7 |
0.5 0.5 7.7 |
|
| Strangers | 3.6 | 8.2 | 4.8 | 0.0 | 4.8 | |
| Relationship unknown | 92.7 | 78.7 | 79.4 | 90.0 | 84.2 | |
Table 8 lists the relationship, if any, between the victim and offender for all cases, closed cases, and open cases. The offender and victim were strangers prior to the homicide incident in 23.6% of the cases. In 53.1% of the cases they had known each other. In 23.3% of the cases the relationship between victim and offender was unknown. The victim and offender were members of the same family in 7.8% of the cases. They were related by blood in 4.7% of the cases and related by marriage in 2.3%. In 0.8% of the cases the victim and offender were related but their relationship was unspecified. They lived together in 8.6% of the cases. In 6.3% (n = 50) of the cases the victim and offender had a romantic relationship in either the immediate or distant past.
With regard to differences between cities, the victim and offender knew each other more often in City D than in the other cities. Also, City B and City D had a high percentage of cases in which the victim and offender were members of the same family.
Investigative Process
This section describes the efforts made by the police in investigating the homicides. It also describes the evidence found at the scene, the amount of time it took to close the case, and the most important reason the case was open or closed.
The majority of homicide cases are handled by one or two detectives. One detective was assigned to 23.7% of the cases and two detectives were assigned to 41.6% of the cases. More than two detectives were assigned to 34.5% of the cases. However, 15.5% of those cases were handled by 11 homicide detectives and these cases were all from City D.
The detective assigned to the homicide went to the crime scene in 90.4% of the cases. The crime scene was a public place (street or park) in 52.4% of the cases. The homicides occurred in a private residence 34.2% of the time. The remainder of cases occurred in a commercial establishment. Only 2% of the homicides occurred in a bar or club.
A search warrant was necessary for the crime scene for 3.2% of the cases. A search warrant was issued for another location besides the crime scene in 14.9% of the cases. When a search warrant was issued for another location besides the crime scene, 68.9% (82 cases) of the time the location was the suspect’s home. A search warrant was issued for a total of 138 (17.2%) cases in our sample.
The crime scene was secured by the first officer on the scene in 87.1% of the cases. The first officer on the scene protected the scene, notified the homicide unit, notified the medic, notified the crime lab, and attempted to locate witnesses in over 90% of the cases. In over 70% of the cases the crime scene was secured within 10 minutes. The majority of crime scenes were kept secure for 2 to 5 hours.
Evidence technicians are responsible for collecting evidence at a crime scene. Some form of physical evidence was discovered in 72.8% (581) of the cases. In cases in which physical evidence was found, 8.8% of the time fingerprints were located. Of the 600 cases in which a gun was used, a bullet was found 33.7% (202 cases) of the time and shell casings were found 63.7% (382 cases) of the time.
A witness was found at the crime scene in 80.3% of the cases. In 19.4% of the cases no witnesses were found at the crime scene, and for 0.3% of the cases this information was missing. When witnesses were found at the crime scene, they were interviewed 97.5% of the time. In approximately 60% of the cases the witnesses were interviewed by both the first officer on the scene and the homicide detective assigned to the case. Of the cases in which witnesses were interviewed, 85.6% of the witnesses were interviewed at the police department and 13.8% were interviewed at just the crime scene. The location for the interview was unknown for 0.6% of the cases. The interviews lasted less than 2 hours per witness for approximately 90% of the cases.
The witnesses at the scene provide valuable information to the police in 65% of the cases. A witness described the circumstances of the death 50.8% of the time and the motivation for the death 31% of the time. For 30.2% of the cases, a witness identified the physical characteristics of the offender and in 39.2% of the cases a witness identified the offender. The identification of the victim was provided by a witness for 27.4% of the cases. The location of the offender was discovered for 8.9% of the cases by way of a witness and a witness identified a vehicle connected with the homicide for 14.2% of the cases.
The police conducted a neighborhood survey in 61.2% of the homicide cases. A neighborhood survey consists of the police going door to door asking neighbors if they saw or heard anything. In our sample, as few as 1 officer and as many as 15 officers conducted the survey. However, the average number of officers who conducted a neighborhood survey was 2. When a neighborhood survey was conducted, 35.3% of the time the police discovered some form of valuable information.
In addition to conducting a neighborhood survey the police also interviewed family, friends, and coworkers of the deceased. Family members were interviewed in 54.4% of the cases, friends were interviewed in 46.4% of the cases, and coworkers were interviewed in 3.9% of the cases. These interviews provided the circumstances of the death in 7.8% of the cases and the motivation for the death in 7.3% of the cases. An offender was identified in 7% of the cases and the characteristics of the offender were provided in 4% of the cases due to these interviews. These interviews also provided the identification of the victim in 31.7% of the cases, the location of an offender in 1.9% of the cases, and the description of a vehicle used in the homicide in 2.8% of the cases.
In addition to interviews, the police also conduct a computer check on the decedent; the suspect; witnesses; and any guns, shell casings, or vehicles involved in the homicide. A computer check for any prior criminal record was conducted 66.9% of the time for decedents, 64.9% of the time for suspects, and 38.3% of the time for witnesses. A computer check was run on guns 16.9% of the time when a gun was found. When shell casings were found, a computer check was conducted 22.7% of the time, and when a vehicle was involved, a check was run 46% of the time. These computer checks provided valuable information to the police in only 15.2% of the cases in our sample.
The police also use confidential informants, other officers, and surveillance in their quest to solve a case. A confidential informant was used in 12.8% of the cases. They provided valuable information in 65.7% of the cases in which they were used. Other police officers were used in 7.9% of the homicide cases. When another officer besides the detective assigned to the case provided information, 95.2% of the time the information proved valuable to the investigation. Surveillance was used in 4.4% of the cases. Approximately 70% of the time the surveillance was used on a suspect, the suspect’s residence, or possible locations of the suspect. The surveillance provided valuable information in 71.4% of the cases in which it was used.
In addition to actively looking for information, the police also accumulate information from witnesses who come forward on their own. In 31.3% of the homicides, witnesses came forward on their own accord. When witnesses did come forward, they provided valuable information 87.6% of the time. Valuable information consists of circumstances of the death, motivation for the homicide, identifying the offender, providing characteristics of the offender, identifying the victim, identifying a vehicle used in the homicide, or providing the location of the offender. In 61.2% of the cases in which a witness provided valuable information, the witness either identified the offender or confirmed the offender’s identity.
The detective assigned to the homicide was present at the postmortem examination in 58.4% of the cases. Specimens such as blood, hair, fibers, fingernail scrapings, and seminal fluid were collected in 76.3% of the cases. During the examination, projectiles were recovered in 83% of the cases in which a gun was used.
After detectives gather information during the initial stages of the investigation, they follow up on that information. In 91.7% of the cases the detective followed up on information provided by witnesses. The follow-up provided valuable information in 67% of the cases. In 42.9% of the cases in which detectives followed up on information, the follow-up led to the identity of a suspect/offender. The location of the offender was discovered in 18% of the followed-up cases, and the motivation for the death was ascertained for 5% of the cases as a result of following up on witness information.
An arrest warrant was requested and issued for 59.4% of the suspects in our sample. An arrest warrant was served and the suspect was arrested in 57% of the cases. A suspect was identified but no warrant was issued for 16.1% of the cases. Of those cases, 50.8% of the suspects were already in custody, so an arrest warrant was not necessary.
Table 9 lists the most important reasons in closing the case. A witness identifying the offender was the most prevalent reason in closing a case. In 47.7% of the closed cases a witness identifying the offender was the most significant reason in closing the case. An offender being arrested at or near the crime scene was the second most prevalent reason for closing a case. This occurred in 18% of the closed cases. In 11.9% of the closed cases, the crime was solved by the homicide detective identifying someone who identified the offender—for example, the police located a witness who left the homicide scene or found a friend/family member of the decedent who knew why someone would want to harm the decedent.
Table 9 Reasons for Closing the Case
| Reason | Percent of Cases (N) |
||||
| City A | City B | City C | City D | All Cities | |
| Witnesses at scene identified the offender | 45.5 (66) |
50.4 (70) |
57.0 (77) |
40.0 (68) |
47.7 (281) |
| Offender arrested at or near the scene | 11.7 (17) |
17.3 (24) |
14.8 (20) |
26.5 (45) |
18.0 (106) |
| Investigator identified those who identified the offender | 15.2 (22) |
12.9 (18) |
4.4 (6) |
14.1 (24) |
11.9 (70) |
| Method of crime linked to offender | 11.7 (17) |
5.8 (8) |
5.2 (7) |
14.7 (25) |
9.7 (57) |
| Information supplied by others | 13.1 (19) |
||||