An off-duty NYPD cop is believed to have shot and killed another man on Long Island, police said Wednesday morning.

Nassau County cops responded just after 8 p.m. Tuesday to a shooting that occurred in front of a home on Langdon Road in Farmingdale, authorities said.

Upon arrival, cops found a 25-year-old man who had suffered fatal gunshot wounds.

The NYPD confirmed that a male officer is believed to be the shooter.

There is no immediate word on arrests and Nassau police are continuing to investigate.