Nassau County police are on the lookout for an NYPD-cop impersonator who pulled off two robberies in Westbury.

In the first case, a man and woman were confronted by the suspect — a man in his 40s wearing a dark, puffy jacket and NYPD turtleneck — as they sat in their car Thursday.

The thug announced he was an officer and ordered the woman into the back seat before making off with money, jewelry and cellphones, police said.

Then, just before midnight, a woman was approached by a man fitting the suspect’s description as she sat in her car at a mall parking lot. But the suspect fled as she locked the doors. No one was injured.