A New Jersey driver was nabbed by an off-duty MTA police officer after fatally mowing down a woman on a bicycle in Tribeca on Saturday night and then speeding off, cops said.

Samuel Silva, 26, was making a right turn on Chambers Street from West Street in his Ford truck when he struck the woman, who was riding her bike south on West Street, around 8 p.m.

The woman, who had no identification on her, was taken to Bellevue Hospital, where she died.

Silva sped away, but a witness told an off-duty MTA cop who was traveling north on West Street which way the hit-and-run driver went.

The cop did a U-turn and found Silva sitting in his F-150 nearby, police said.

The MTA officer, who wasn’t identified, notified the NYPD, police said.

Silva was arrested near Warren Street and North End Avenue. The NYPD Collision Investigation Squad investigated.

Silva, of Newark, was charged with manslaughter, leaving the scene of an accident, failure to yield to a pedestrian and driving while ability impaired, police said.