Suspected NYC cop-killer stashed shiv in body cavity in case he needed it that night: police source

The ex-con suspected of killing an NYPD cop was so conditioned to crime that he had a shiv stashed in his rectum that night — anticipating he might be busted for something, a police source said Tuesday.

Guy Rivera, 34, was in the passenger seat of a Kia Soul around 5:50 p.m. Monday in Far Rockaway, Queens, when a couple of NYPD “quality-of-life” cops, including Officer Jonathan Diller, spotted it illegally parked in a bus stop, the high-ranking source said.

An ensuing confrontation left Diller, a 31-year-old married dad, dead — allegedly shot through the stomach by Rivera.

Rivera was wounded when the cop’s partner returned fire, and he was taken to the hospital, where an X-ray revealed he had a homemade shiv — a sharp razor or smallish knife — hidden in his butt, the source said.

Cops believe he had the weapon — which was shorter than 4 inches and therefore not illegal — because he expected he could be arrested for a crime that day and wanted it for self-defense if he went to jail, the source said.

It wasn’t clear what kind of crime he might have been allegedly contemplating.