(NewsNation) — U.S. marshals have just 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. And now federal officials are asking citizens to be on the lookout.

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.

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 trek.

After squeezing through a vent and scaling pipes that led to the prison roof, the trio traversed 100 feet across the rooftop and then carefully maneuvered down 50 feet of piping to the ground.

After reaching the outer walls, they launched a makeshift raft of more than 50 raincoats in hopes of making it off the island. The following morning, guards awoke to find three detailed makeshift heads, made up of plaster, paint and real human hair in their cell beds.

The escape inspired the 1979 film “Escape From Alcatraz” starring Clint Eastwood.

The prison was immediately put into lockdown, but the convicts had already gained a 10-hour lead on investigators. Authorities worked for weeks to locate the inmates but found no sign of any evidence.

Federal officials later said that they believed the inmates had drowned.

Now, 60 years later, theories have tested whether or not that is true. A raft was recovered on a nearby island shortly after their escape, and there were accounts of a car being stolen the night of the disappearance.

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.

The letter forced U.S. marshals to reopen the case, and now, investigators hope the new re-aged images will help crack it.