This article published by USA Today discusses the developing partnerships between city police forces and the Bureau of Alcohol, Tobacco, Firearms and Explosives to use shell casing data to find and arrest violent criminals.
The Denver Police Department has already been working with ATF for two years and has prosecuted 34 suspects that are in the process of being put away for more than 50 shootings. In addition, thirteen have been prosecuted on the federal level.
The article explains how federal agents utilize a database of shell casing photographs to discover which particular gun was used in a crime. Each gun leaves distinctive markings on the shell casings, like a fingerprint, so law enforcement can determine the exact gun used in a crime by matching a shell casing to one already stored in a database. If police can accurately determine the gun, then they can trace the gun to the person who committed the crime.
The new method has revealed that a certain gun is often used in multiple crimes in a particular area by the same person. When that person is arrested, it reduces the total crime in the area by removing the person from that neighborhood that is responsible for a large amount of crime there.
The Department of Justice gave a $500,000 grant to fund the initial project and it appears that it will likely grant more money in the future.
The success of the partnership with Denver has led the ATF to pursue new partnerships with Nashville, Baltimore, Seattle, Los Angeles, Phoenix and Colorado Springs.
The article is well sourced and has substantial quotes from the federal ATF agent assigned to the Denver area, the Denver Police Commissioner and the U.S Attorney for Colorado.
It also has informative statistics about the increase in prosecutions and the drop in crimes involving guns since the implementation of the program.