Despite fine physical conditioning, a susceptibility to epileptic seizures contributed to a young New Yorker's drowning death off Mantoloking on July 4, according to findings by the Ocean County Medical Examiner.

Map showing area where drowning victim John A. Crimmins, 22, of Yonkers was found (Ocean County Prosecutor's Office)

John A. Crimmins, 22, was an avid surfer and lifeguard who appeared to be in no distress during a swim with friends, investigators in County Prosecutor Joseph A. Coronato's office said. He disappeared from their sight, and was spotted about a half-hour later by lifeguards in a Bay Head enclave.

Dr. Lydia Perez listed the cause of death as drowning, "naming idiopathic epileptic seizures contributing to the event."

The investigation has been closed, with investigators in the Prosecutor's office extending condolences to Crimmins's family and friends.