The son of a drug rehabilitation expert was killed and another man was wounded on a busy Berkeley street Tuesday by a pair of gunmen who raked them with shots and then ran away as horrified shopkeepers were opening their businesses for the day.

Residents of the economically depressed neighborhood said they believed the attack was over gang or drug-dealer turf, but most were afraid to talk openly. Police said the victims appeared to have been targeted.

When the shooting near the corner of Sacramento and Russell streets erupted at 8:45 a.m., attorney Paul Clifford thought it was firecrackers going off.

"I heard the shots, looked out the window and saw the bodies," said Clifford, whose office is across the street. "One of the men was cradling the other, just sitting there and comforting him."

By the time he looked out his window, the shooters had already run from the scene and a crowd was beginning to gather.

The victims were in the driveway of a Pacific Gas and Electric Co. substation, next to a laundry. Witnesses said the killers had fired dozens of shots.

The Alameda County coroner's office identified the slain man as Gary Ferguson Jr., 35, of Oakland. Witnesses and friends of the family said he had struggled with drug addiction, which alarmed his father, Gary Ferguson Sr., who ran a drug rehabilitation center for years in Berkeley.

The elder Ferguson, a former heroin addict, was director of the Sobriety Through Education and Peer Support program until it shut because of funding shortages two years ago. He could not be reached for comment.

"That center was a real personal passion of his, and we in the community celebrated and highlighted Gary (Sr.) as a champion of having gone to hell and back, showing people how you can overcome addiction, too," said Alameda County Supervisor Keith Carson, a friend of the family.

Carson said that about a year ago, Ferguson told him he was having troubles with his son, and that the son "had fallen into addiction."

"As much as he was working to change other peoples' lives and was so passionate about it, he was unable to fully do the same thing with his son," Carson said. "It made him very sad."

Those in the neighborhood who might know about the final moments of the younger Ferguson's life weren't readily offering information Tuesday.

"It's no mystery what goes on here, but you don't want to know," said one of several young men clustered in front of a small grocery near the scene. "Just keep walking."

The surviving gunshot victim underwent surgery at a local hospital and was in stable condition, said police Sgt. Mary Kusmiss. No arrests have been made, and there was no description of the suspects.

The neighborhood, which stretches north from the busy corner of Ashby Avenue and Sacramento, was relatively quiet for a few years, residents said. But in the past several months, three shootings and several assaults and robberies have shattered any sense of calm.

"I don't come down this way if I can help it," Lois Stephens, who lives a couple of blocks away, said as she stood alongside a check-cashing business and watched police sweeping for evidence. "Too much trouble here."

Catherine Johnson, who has run the Just Cuts barbershop across the street from the killing scene for 27 years, said she thinks the neighborhood's troubles would be eased if there were more for the ubiquitous groups of idle youngsters to do.

"Anytime you get a lot of loitering young people just hanging out, that's when trouble happens," Johnson said as she cut a young man's hair. "And that's what we've been having."

Chronicle staff writer Henry K. Lee contributed to this report.