The New York Police Department has warned officers to watch out for a type of rare custom-made pistol, disguised as a cell phone.
Federal authorities have been issuing warnings about the specially made .22 caliber handgun since at least 2000, when several were recovered by law enforcement authorities in Europe.
The weapons, which use a spring-wound percussion system to fire up to four .22 caliber bullets, have continued to surface occasionally overseas.
The NYPD issued a warning to its commanders about the weapon in a directive on May 11, the New York Post reported.
The memo included pictures of the weapon and a description of how it works. It asked police conducting security screening at police headquarters or borough courthouses to be cautious handling cell phones during searches.
Video of the pistol in action has circulated widely on the Internet.