The accident happened at West 29th and 9th Avenue in Chelsea around noon.
Police say Marilyn Dershowitz, a retired Manhattan state Supreme Court special referee who was the sister-in-law of prominent lawyer Alan Dershowitz, hit by a U.S. Postal Service truck while riding her bicycle on 29th Street. She was pronounced dead at Bellevue Hospital.
The truck drove off, apparently unaware that a cyclist had been struck.
The driver and vehicle were eventually located. No charges have been filed.
Dershowitz retired in December. She had overseen divorce trials, including the proceedings of Dr. Nicholas Bartha and his wife.
The physician blew up the family's East Side town house and killed himself in 2006 so his former wife wouldn't benefit from its sale.
Dershowitz was the sister-in-law of Alan Dershowitz, a well-known attorney at Harvard University.