PHILADELPHIA (CBS) - Two Upper Darby teenagers are in jail, accused of beating a 34-year-old man into a coma early Friday morning.

Upper Darby police chief Mike Chitwood says the attack occurred about 1:15 Friday morning as the 34-year-old victim was walking to his home on Lamport Road.

Chitwood says it's not clear what started the altercation with the three teens. He says 19-year-old Jeremiah Alexander (photo) is accused of knocking the man down and kicking him and the others joined in.

"It looks like it was just a gang mentality, a wolf pack attack and one guy punched and then they just started kicking and stomping," he said.

A 16-year-old girl is charged in the case with stomping the victim so hard, she left her shoe imprint on his face.

Alexander is being held on $50,000 bail. The 16-year-old is in Delaware County juvenile detention.

Reported By Pat Loeb, KYW Newsradio.