(NewsNation) — Earlier this week, U.S. marshals released age-progression images of convicts who escaped Alcatraz Island more than 60 years ago.

Over the years, speculation has mounted over whether or not the escaped prisoners are still alive.

Clarence Anglin, John Anglin and Frank Morris remain wanted fugitives for their June 11, 1962 escape from Alcatraz, where they were serving time for armed bank robberies.

“It’s not very likely that they’re alive,” Michael Dyke, the former head investigator of the case, said during a Wednesday appearance on “NewsNation Prime.” “Even at their advanced age, it’s not likely (that) if they lived through the escape that they’d be alive. I’m more of the opinion that they didn’t’ make it through that first night.”

The three men spent more than a year organizing and planning their escape, setting up a secret workshop on top of their cells, as well as stockpiling the tools and resources needed to make the dangerous journey.

Dyke said the escapees left at the worst time possible due to the ocean currents and that it’s not likely they even made it to land.

It has, however, been reported that the escapees launched a makeshift raft made of more than 50 raincoats, and there were accounts of a car being stolen the night of the disappearance.

Dyke said it’s possible that a raft like that could have worked, but one of the escapees would have had to constantly inflate the raft while the other two paddled.

“As far as the car missing, that was reported a day or two later by someone (saying) the car ran off the road. They said it was occupied by at least two people. They said it might have been stolen from Marin County. There’s actually no way, right now, to go back and double check all that because all those records have been purged,” Dyke said.

In 2013, authorities received a handwritten letter by a man claiming to be John Anglin, asking for a light sentence in return for medical attention.

Dyke looked into the letter thoroughly and said the handwriting wasn’t even close to replicating any of the escapees handwriting.