An NYPD officer sold out his badge - and handed over his gun and other police equipment - to a crime crew that posed as cops to rob drug dealers, the feds charged Thursday.

Emmanuel Tavarez even took part in at least four of the stickups, acting as lookout in case real cops showed up, authorities said.

Tavarez, an eight-year veteran with a bodybuilder's physique, pleaded not guilty to an indictment in Brooklyn Federal Court, answering each of the judge's questions with a crisp "yes, sir."

Held without bail, he faces life in prison if convicted of robbery and drug charges.

"The crimes alleged to have been committed by Emmanuel Tavarez are a slap in the face to the vast majority of law enforcement officers in New York City who are dedicated to upholding the law," said John Gilbride, special agent in charge of the Drug Enforcement Administration in New York.

The feds have already charged 15 other crew members with pulling more than 100 robberies of drug dealers in New York City, Connecticut, New Jersey and Pennsylvania since 2001.

Tavarez, 30, related by marriage to four co-defendants, provided the gang with NYPD raid jackets and other police paraphernalia so they would look like the real thing.

"On more than one occasion, Tavarez also handed his firearm to a member of the robbery crew to embolden him to go through with the robbery," prosecutor Stephen Meyer stated in court papers.

Another time, Tavarez provided his police utility belt, holster, firearm and bullet-proof vest to crew members going into an apartment building for a robbery, Meyer said.

After standing watch on the street, Tavarez went inside and told the victims it was a police drug raid.

The crew also had an auto customized with police-style lights and a speaker they used to pull over their marks. Tavarez's lawyer declined to comment