The Violin Case Murders.

The first film adaptation of Jerry Cotton. FBI agents Jerry Cotton and Phil Decker are tracing a group of six murderers. Disguised as a vagabond Jerry Cotton infiltrates the gang. Kitty, the leader's girlfriend, soon becomes Jerry's most important helper. With her help, he's able to prevent a bomb's explosion in a school. The deadly attack on a rich collector he can not prevent. The gangsters flee with the loot and a hunt to the death begins ...