ATLANTA -- A former Marine cook fatally stabbed one teenager and wounded a second while fending off a robbery by a group of youths armed with two guns and a pair of brass knuckles, police said.

Thomas Autry, 36, acted in self-defense when the suspects jumped him around 11 p.m. Monday, and he will not face charges, police spokeswoman Sylvia Abernathy said.

"The victim, in fear for his life, retaliated with a pocket knife that he had," Abernathy said. "It was apparent that they were going to rob him."

The girl he stabbed, Amy Martin, 17, was pronounced dead at a nearby hospital. The accomplice who was wounded, Christopher Daniel, 17, was listed in critical condition at Atlanta Medical Center, Abernathy said.

Daniel and three other youths involved in the robbery -- a 16-year-old and 17-year-olds Kendall Barksdale and Christopher Hayes -- were charged with aggravated assault and armed robbery.

The day after the attack, Autry, cigar in his mouth and bandage on his index finger, returned to his girlfriend's apartment, where he had the locks changed. He told reporters he doesn't feel like a hero.

"The heroes are the ones fighting over there every day for our country and not getting any respect," said Autry, who was stationed in Saudi Arabia during the first Gulf War.

Of the attack, he said, "It wasn't admirable."

"It was either fight or flight," he added. "I tried the flight but they caught me."

Police said the suspects, armed with a shotgun, handgun and brass knuckles, jumped on Autry and tried to rob him.

After the attack, the suspects ran back to their car and drove off.

Police found them later at a hospital, where the teenage girl died. She had suffered a single stab wound to the chest, said Dr. Michele Stauffenberg, who conducted the autopsy for the Fulton County Medical Examiner's Office.

Autry suffered a cut to his hand and a bruise on his chest.

Police are investigating whether the youths were involved in other unsolved robberies in the area, but investigators have yet to connect them to any, Abernathy said.

Police credited Autry's military training with helping him fend off his attackers.

Autry said he was honorably discharged from the Marines in 1992 after serving for four years. The Department of Defense confirmed his service, but would not provide any details.