SAN FRANCISCO (CBS 5) – More than four decades after the most famous escape attempt from Alcatraz, the investigation continues into the disappearance of three fugitive inmates. One of the men continuing the search tells CBS 5 there is a good chance the men escaped “The Rock” alive.

Frank Morris, Clarence Anglin and his brother John Anglin escaped their cells through vent systems on Alcatraz on the night of June 11th, 1962. The men left dummy heads in their beds and scrambled up a series of pipes, ran across the prison roof and may have inflated a raft before heading towards shore. The men were never found, and for years have been presumed dead.

READ MORE: 1 Dead, 2 Injured In Separate Falls During Phish Concert At Chase Center

“We just don’t give up looking for anybody,” said Supervising Deputy Mike Dyke of the U.S. Marshals Service. “I think probably the brothers lived… but there’s a chance that all three of them could have lived and they just split up once they left. There’s no body recovered. I can’t close the case.”

Dyke has been working on the case since 2003.

“Some teletypes that indicate there was possibly a raft recovered on Angel Island…the day after the escape – and one of them mentioned footprints leading away from the raft,” said Dyke.  “They came across an oar, a paddle…right off the coast, about 50 yards from the shore of Angel Island.”

“They determined the oar was made on Alcatraz. There was one oar left behind and this one was an exact match,” he continued.

READ MORE: UPDATE: Alameda Businesses Fight Back Against Serial ADA Lawsuit Filer

The issue of the raft is key. If they made it to land, and avoided the cold water, their chances of survival were greatly improved.

“There’s still a chance. You can’t rule out the fact that they died. But you can’t rule out the fact that they lived. That’s why we still have the warrants for them,” said Dyke.

The only problem is that no actual raft was ever found on Angel Island, there was only teletype evidence from the FBI. But if the men made it safely to land, there is still a chance they are alive today.

Clarence Anglin would be 79, his brother John would be 80, and Morris would be 84.

The National Geographic Channel is scheduled to air a documentary Wednesday night based on Dyke’s investigation.

MORE NEWS: UPDATE: Cal Fire Officials Discuss How Controlled Burn Erupted Into Estrada Fire

(© 2011 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)