PHILADELPHIA (CBS) – An off-duty Philadelphia police sergeant rescued by Good Samaritans after his car crashed into the Schuylkill River on Tuesday afternoon has died.

55-year-old Stephen Naughton, a 31-year veteran, lost control of his car while driving along Kelly Drive near Strawberry Mansion Bridge Drive and crashed into the river at about 4 p.m., according to police.

Two bicyclists and a police officer witnessed the crash and jumped into the water to pull the man from the submerged vehicle.

“I tried to yell to get a response from the victim, couldn’t get anything, so I jumped in and had a real hard time finding the seat belt and at that point the car was under the water,” explained one of the rescuers. “I got some extra help from some other people, we got the seat belt loose, however, again, we struggled to get the victim out of the car.”

Sergeant Naughton was taken to Hahnemann University Hospital where he was pronounced dead.

Police Commissioner Charles Ramsey and Mayor Michael Nutter rushed to the hospital to offer support to the officer’s wife and two children.

“I’m very, very saddened, as the whole city is, to lose one of our officers,” said Nutter.

Naughton had been assigned to the Community Relations Unit.

Medical examiners say Naughton suffered a heart attack before loosing control of his vehicle.

Reported by Walt Hunter, CBS 3