The caper story is a special sort of crime story. In the typical caper story, one or more crimes happen (especially thefts, swindles, or occasionally kidnappings) in full view of the reader. The actions of the police or detectives may also be told, but are not that important for the story.
Examples of the caper story
The Dortmunder stories of Donald E. Westlake are very funny tales where unusual thefts happen; in another story, Dortmunder's gang steals the same gem several times, steals an entire branch bank, and kidnaps someone from an asylum by driving a stolen train onto the property.