Green’s Dictionary of Slang

to commit a crime, esp. as a professional thief.

1969		B. Jackson Thief’s Primer 36: Someone who was arrested for stealing a car to joy-ride around town [...] You know he really can’t caper.
1976		M. Braly False Starts 211: I know you’re capering [...] Do you want a partner?
1990		S. Morgan Homeboy 89: Harold and Joe had capered together [...] though petty boosting only.