Pleasanton police said Wednesday they have identified four people who were there when someone attacked 51-year-old David Lamont outside his house over the weekend.
The brutal beating was reported just after midnight Saturday morning when Lamont went to check out some voices and noises outside his home on Middleton Place.
His wife of nearly 25 years, Agnes Lamont, went to search for him when he didn't return and found her husband lying in the street bleeding and unconscious.
Police say they have talked to three teens they are calling witnesses.
There is also someone they are calling a person of interest, an 18-year-old who is not from the area and is not in Pleasanton right now.
Police say they are not releasing any names because the investigation is still under way.
Detectives hope they can talk to Lamont about the attack soon. As of Monday night, he was in a coma at Eden Medical Center. NBC Bay Area spoke with Lamont's wife Wednesday afternoon. She says her husband's condition has not improved.