Each gun recovered by the police, whether or not connected to an arrest, must be tested ballistically against evidence from pending cases. Every shell casing and spent bullet from a crime scene was checked by the ballistics squad. This was being done in New York City with the aid of federal agents. Over 100 firearms or casings were matched with other crime scenes, providing valuable leads to detectives. All prisoners in New York City are questioned by detectives as to their knowledge regarding the illegal sale or storage of firearms.
Many criminals talk.
Search warrants are obtained and firearms confiscated. This questioning of prisoners also reveals valuable intelligence on other crimes. It allows detectives to discover motives, find witnesses and locate offenders wanted for many crimes. Results of individual debriefings are reviewed by detective supervisors to assure quality and thoroughness of the questioning. Computer Mapping was made available to detective commanders.