After a wave of gun violence in Seattle, KING 5 examined some of the most basic techniques that police use to solve gun crimes. By analyzing documents received through public records requests the television station learned that most large police departments in Washington state are not conducting routine ballistics tests on the so-called “crime guns” they seize from suspects and crime scenes. This means that guns, that could hold clues to unsolved crimes, are sitting right under investigators' noses in their own evidence rooms. The investigative series "Trail of the Gun" also unearthed the results of federal firearms “traces”, which police use to determine how a gun ended up in the hands of a criminal. These trace results revealed that a large number of Seattle's crime guns came from an unexpected place. After the stories aired, several large police departments pledged to begin ballistics testing programs for their crime guns. The Federal Bureau of Alcohol, Tobacco and Firearms offered to assist local police agencies to test every gun in their evidence rooms. And, the feds unveiled a warrant targeting one of the gun dealers identified in the series.