Updated 06/19/11 – 6:19 a.m.

CHICAGO (CBS) — A 5-year-old boy is dead after falling into Jackson Park Harbor.

As CBS 2’s Derrick Blakley reports, the boy, identified as Tyrone White, was rescued from the water by firefighters and passersby, but he could not be saved. He was pronounced dead at 5:28 p.m. at the University of Chicago’s Comer Children’s Hospital.

Witnesses said Tyrone might have been in the water for 20 minutes before his body was finally recovered by Fire Department divers.

The boy was walking with his family down a pier when he fell in the water about 4:20 p.m., Fire Media Affairs Chief Joe Roccasalva said.

The incident happened about 6500 South Promontory Drive, according to police News Affairs Officer Darryl Baety. The location is near the Jackson Park Yacht Club.

It is not clear how Tyrone fell into the water. One witness said he might have dropped a walkie-talkie into the water, and then might have fallen in to retrieve it.

By all accounts, the boy was not wearing a life vest.

Boaters at the marina frantically dialed 911, and six or seven of them — among them the boy’s father — dived in themselves trying to save the child.

“I was up on the porch and I heard somebody screaming. I did not see the boy go in, but I was in the water diving to get to the bottom,” said witness Gloria Fallon. “I went down – I don’t know – 10 or 15 times, but there’s only 2 or 3 feet of visibility, and when you got down, you couldn’t touch the bottom, because it would bring up the mud and you couldn’t see anything at all. I just had a pair of goggles on, and I was pretty close to where they pulled him out, but I didn’t see him.”

“Please put your children in life vests, because this is a very scary moment,” a man, Tony, said as his voice cracked. “Please do that, because it can happen in a blink of an eye.”

Emergency crews responded with firefighters and paramedics, and a helicopter was even launched. But it took a while for Fire Department divers to arrive, and they were the ones who finally recovered the body from the murky waters of the harbor. But it was simply too late.

(The Sun-Times Media Wire contributed to this report.)