Tobay Beach was temporarily closed Friday after a lifeguard found "unknown organ parts" -- later determined not to be human -- floating in the water, Nassau County police said.
Police said Seventh Squad and Homicide detectives were called to the beach just before 1 p.m., after a lifeguard working on the bay side of the beach "observed and gathered unknown organ parts floating in the water."
The beach was then closed and evacuated.
The remains were taken to the Nassau County medical examiner's office, which determined the remains were "not human," police said.
The beach, which is reserved primarily for Oyster Bay town residents, reopened at 3:15 p.m. with no restrictions, police said.