Federal Operator 99 is a 1945 Republic film serial in 12 chapters. The serial is about an FBI agent named Jerry Blake who battles "gentleman thief" Jim Belmont, who escapes custody with help of his gang and begins a wave of crimes.

Crime Lord James 'Jim' Belmont (George J. Lewis) escapes FBI custody and resumes his criminal empire, only to be thwarted at every turning point by Jerry Blake, the FBI's Operator 99 (Marten Lamont). Belmont plots to steal the crown jewels of the Princess Cornelia, with the aid of his cohorts Matt Farrell, Rita Parker and his crafty secretary Morton. The criminals succeed in stealing the jewels, then offer to ransom them back, using Jerry Blake (Operator 99) as the go-between. Blake foils their plot and also acts against different criminal engagements by Belmont such as trying to steal a car once owned by Belmont’s partner, a car into which valuable gold has been melted and whose location is known by a former lawyer who worked for Belmont.

Cast

Marten Lamont as Jerry Blake, Federal Operator 99
Helen Talbot as Joyce Kingston
George J. Lewis as Jim Belmont, a sophisticated villain
Lorna Gray as Rita Parker, Belmont's partner in crime
Hal Taliaferro as Matt Farrell
Bill Stevens as Agent Fred Martin

text from wikipedia