CUPERTINO, Calif. » An hour had passed and three of their colleagues lay dead when surviving workers at a Silicon Valley cement plant heard an ominous voice on a work-issued walkie-talkie: the gunman, who’d fled the bloody scene, was vowing to return.

"He says something to the effect of, ‘I’m watching you and I’m going to come back and finish you off!’" said Sgt. Jose Cardoza, a spokesman with the Santa Clara County Sheriff’s Office.

The chilling account emerged Friday as authorities provided new details about how Shareef Allman shot his terrified victims, all co-workers, killing three and wounding six others.

The violence began around 4 a.m. Wednesday, when about a dozen employees at Lehigh Southwest Cement plant assembled in a small room for a security meeting, Jose Rivas, 49, a survivor who worked on a conveyor belt at the company, told The Associated Press.

Allman, 47, a truck driver who had been having problems at work and was angry over a recent suspension, entered the room around 15 minutes after the meeting started.

"He doesn’t even say ‘Good morning,’" Rivas recalled. "He just came in and grabbed a cup of coffee."

Rivas said Allman walked around the room and then left.

About five minutes later, Allman returned, barricaded the door and opened fire, Cardoza said. Rivas said Allman yelled an obscenity before shooting.

He shot 59-year-old Mark Munoz first, Rivas said, then picked off the others one by one. Munoz died, as did Manuel Pinon, 48, and John Vallejos, 51.

Rivas, who was sitting in a chair on the perimeter of the room when the shooting began, dove under a table. He saw his supervisor, Jose Hernandez, get shot.

"He yelled ‘No, no, no,’" Rivas said of Hernandez. Allman then walked to each person hiding under the table and shot them, Rivas said.

Rivas put his head down on his arm, and waited his turn.

"He was ready to shoot me. I said, ‘No, no!," said Rivas as he screwed up his face to mimic Allman’s enraged mien. "It was terrible. He was filled with hate."

Allman passed Rivas over, continuing to shoot others.

"I saw my boss laying there bleeding. Then it stopped. Then we heard steps," Rivas said.

Hernandez then told Rivas to call 911, who hesitated for a few seconds, worried that Allman was still outside. But then Rivas ran to another part of the office.

"I jumped over the bodies," he said. "I ran to part of the office and then I called 911. I said, ‘Send the police! Send an ambulance! Please, please we need help.’"

Allman left the room, police said, leaving the cement plant before shooting a Hewlett-Packard contract employee in the leg while trying to carjack her. An update on her injuries wasn’t immediately available Friday; she has been listed in fair condition.

Surveillance video shows Allman walked through a gas station nearby at about the same time, a rifle slung over his shoulder.

Allman then disappeared into a quiet Sunnyvale neighborhood, leading to an intense manhunt that ended Thursday morning after three sheriff’s deputies on a routine patrol saw him hiding behind two cars in the driveway of a house.

San Jose attorney Terry Bowman, who represents deputies Fabian De Santiago, Christopher Hilt and Lindsay Crist, said De Santiago saw a figure in his rear view mirror and turned the car around.

"(De Santiago) gets out of the car and he is realizing that this person matches the description of Mr. Allman, and he’s aware of what happened at the quarry and that he is presumed armed and dangerous," Bowman said. "And (De Santiago) is telling him, ‘Let me see your hands! Let me see your hands!’"

Allman put his hands in the air, and the deputies noticed he was holding a handgun, Bowman said.

Bowman said all three deputies reported that Allman made a comment to the effect of "kill me."

"He then points his gun directly at the deputy," Bowman said. "All three deputies see this, and all three fire their weapons in response to the deadly threat."

Authorities have not released any details about a possible motive, other than to say the suspect was disgruntled.

Allman’s friends and colleagues said he had complained about being treated unfairly by his managers, but still were baffled that he resorted to violence. He was described as a pillar of San Jose’s black community, a doting father of two who penned a novel describing the evils of domestic violence.

But Allman recently felt he was wronged by a suspension at work following an accident in which he hit a power line while dumping a truck load at the quarry, according to Bill Hoyt, secretary-treasurer of Teamster’s Local 287.

Hoyt said Allman visited his labor union offices less than a week before the shooting, saying he was being treated unfairly.

Another longtime friend, Walter Wilson, said Allman complained of racism at work, but he didn’t think it was a major issue for him.

"As far as I know he was the only African-American truck driver," Wilson said. "I tried to tell him to go through the process, and he said he felt like he had it under control."

Tom Chizmadia, a spokesman for Lehigh Hanson Inc., the cement plant and quarry’s corporate parent, said there was no racial discrimination.

"The company feels very strongly about diversity in the workforce," he said.

While Allman’s friends were mystified that he could resort to such violent, court documents show that Allman’s ex-wife filed for a restraining order against him in 1991.

In the documents, Valerie Allman said Allman hit her on the side of the head with a brass lamp, knocking her unconscious. She also wrote that Allman once became enraged when he couldn’t find one of the two guns he kept in the house.

But friends said Allman had put his life together, that he preached positivity in life and in his cable access television show "Real 2 Real."

For Rivas, he felt a higher power protected him that day.

Rivas interlocked his fingers, kissed his thumbs and raised his hands to the sky, as he said, "My Lord, my Lord! He put a shell around me like an angel around me."

He later added, "I don’t like the human brain anymore. It’s infected with evil."