An off-duty NYPD officer was killed in a Long Island car crash early Thursday morning, authorities said.

Cops said officer Joseph Capo, 27, was returning to his Long Island home at around 1 a.m. when his car struck another vehicle, causing him to flip multiple times on the Southern State Parkway.

Capo was rushed to Nassau University Medical Center in critical condition, but was later pronounced dead.

Police say Capo was assigned to the 9th precinct in Manhattan, which covers East Village.

An investigation behind the fatal crash is ongoing, officials say.