LOS ANGELES Newly released documents show that a former Los Angeles police officer who's already serving a prison term for drug trafficking admitted he and other officers were behind a series of violent robberies.

Ruben Palomares, an ex-Rampart Division officer, admitted he and his colleagues robbed drugs, cash, guns and other items between 1998 and 2001. The crew of about 20 netted hundreds of thousands of dollars during robberies that were often staged to look like law enforcement raids. However, the spree often turned violent and there were instances where they shot victims with stun guns or beat them with a police baton.

Palomares' guilty plea was part of a deal in which he agreed to cooperate with prosecutors, according to documents obtained by the Los Angeles Times.