The e-newsletter of the COPS Office | Volume 1 | Issue 3 | March 2008

The Rising Trend of Unsolved Homicides

Understanding the problem

While the national homicide rate has fluctuated, the homicide clearance rate has declined steadily, with a drop from 92 percent in 1961 to 61 percent in 2005. This decline results from a number of factors, such as an increase in “stranger homicides,” which are more difficult to solve than “acquaintance homicides.”

During this same period, however, some police departments have maintained consistently high clearance rates. The 90 percent clearance rate of the San Jose, California, Police Department is partially attributable to its mandatory rotation policy, which requires specialized assignment detectives to return to patrol every 5 or 6 years. The logic behind this policy is to maintain a patrol force that includes officers and sergeants with investigative training and experience.

The example of the San Jose Police Department demonstrates that the actions of police departments, responding officers, and homicide investigators can help counteract the decreasing homicide clearance rate.

Encouraging successful investigations

A recent collaboration between the COPS Office and the Police Executive Research Forum has resulted in the resource “Promoting Effective Homicide Investigations,” which aims to address changing trends in homicides and their influence on the declining clearance rate.

This publication outlines practices, policies, and procedures that can increase the number of successful homicide investigations for law enforcement agencies. Also included are examples from several departments that have implemented some of the highlighted practices.

The latest developments in eyewitness identification, videotaped interrogations, and DNA analysis are also discussed in this guide. This information can pertain to homicide and other violent crime investigations. The publication can be downloaded from the COPS Office web site at

Ensuring witness safety

In many communities, the prosecution of homicides may be hindered by witness intimidation, which also often affects the investigations of other crimes, including drug trafficking and gang-related offenses. COPS’ Witness Intimidation, part of the Problem-Oriented Guides for Police (POP Guides) series, includes a number of strategies that ensure the safety of prosecution witnesses. By actively addressing this issue, the law enforcement community can combat community-wide fear from retaliation and attitudes of noncooperation with law enforcement. This publication may be accessed at

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