Green’s Dictionary of Slang

1. (US police) a police officer who makes arrests just to generate overtime salary.

1987

G.W. Clemente Cops are Robbers 127: I had a lot of problems [...] with what police call bounty hunters, the cops that make every arrest they can [...] so that the resulting court appearances make them a substantial amount in overtime.

2. (N.Z. prison) an informer.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 28/1: bounty hunter n. an informer, a nark.