CUPERTINO, Calif. (AP) -- Authorities say they've shot the man suspected of opening fire at a Northern California limestone quarry, killing three co-workers.

Santa Clara County Sheriff's Sgt. Jose Cardoza told the San Jose Mercury News (http://bit.ly/ovdHhs ) that Shareef Allman was shot Thursday morning, but could not confirm if he was killed.

Live television footage shows police cars gathered in a Sunnyvale neighborhood and authorities pulling a tarp over what appears to be a body in front of a home.

Mike Astor, who manages a gas station near the scene, told The Associated Press that he heard gunshots shortly after 7:30 a.m.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

To his friends Shareef Allman was the big man with a big smile, a devoted single father of two who once worked tirelessly to raise money for Hurricane Katrina victims, and who penned a novel about the evils of domestic violence.

The portrait of Allman, 47, being painted by those who know him diverged strongly from the man authorities suspect in the fatal shooting of three co-workers at a cement plant on Wednesday. Seven others were also injured in the attack, some critically, authorities said.

"If you live in San Jose, you could not help but know him. He had a great smile, and he lit up the room. He was such a peaceful man," said Rev. Jeff Moore of the NAACP's San Jose-Silicon Valley chapter. "It's not making any sense to us, and it hurts us to the core. We want to do whatever we can to bring him home."

As the manhunt for Allman continued, his friends pleaded for him to turn himself in while sounding mystified that the man they knew could resort to such brutal behavior.

Allman became upset during a safety meeting at Permanente Quarry, said Santa Clara County sheriff's Lt. Rick Sung. Allman left the meeting and returned with a handgun and rifle and started shooting people, Sung said. About 15 workers were at the meeting.

Sheriff Laurie Smith released the names of the dead Wednesday evening as Manuel Pinon, 48, of Newman, Calif., and John Vallejos, 51 and Mark Munoz, 59, both of San Jose.

"We still believe the suspect is armed and dangerous," Smith said. "How dangerous is he? He murdered three people today."

Six others at the quarry were wounded and taken to hospitals, where some remained in critical condition, Smith said.

After leaving the quarry, authorities received a 911 call at around 7 a.m. reporting that a woman was shot in an attempted carjacking near Hewlett-Packard Co.'s Cupertino campus by a man matching Allman's description. The shooter fled on foot after using a weapon similar to a gun used in the quarry shooting, authorities said.

The carjacking victim, a Hewlett-Packard contract employee, was in fair condition at Santa Clara Valley Medical Center, according to hospital spokeswoman Joy Alexiou. Another victim was treated and released from the hospital, while a third remained in fair condition, she said.

Schools were on lockdown in Cupertino, home of Apple Inc., and in nearby communities as authorities went door to door with guns drawn and residents were warned to stay indoors.

Authorities found Allman's car, and collected a shotgun, a handgun and two rifles believed to belong to the suspect, Santa Clara County Sheriff Laurie Smith said, adding that some of the weapons were found in the car.

Allman was last seen in surveillance footage from a nearby gas station shortly after the shooting outside Hewlett-Packard, Smith said. In the video, he appeared to be armed, she said.

The shootings rattled those close to Allman.

"He was always helping people," said Walter Wilson, a community activist who has known Allman all his life. He said he last saw Allman three weeks ago at downtown music festival, where he seemed happy and jovial. "He spent his life in the service of other people. This is totally out of character for him.

Allman would attend every one of his daughter's basketball games, or any event she was in.

"You talk about Mr. Mom," said Sandra Dailey, 54, who described herself as a close friend. "He never missed an event. He was an incredible father."

In addition to working at the quarry, Allman has run a nonprofit group for youths and produced and hosted a public access television show for CreaTV in San Jose.

He also wrote a novel titled "Saving Grace," about the evils of domestic violence.

On the back cover of the book, Allman wrote a poem and included a statement that the book is not a reflection of himself, but of "man's inhumanity."

In the poem, the subject apologizes for abuse: "How can I say sorry for your blood that I shed? How can I say sorry for almost beating you dead? How can I say sorry, when sorry can't mend the wound? How can I say sorry for the coffin and the tomb?"

Suzanne St. John-Crane, executive director of CreaTV, where Allman submitted video for a television show called Real 2 Real, said she had spoken with him numerous times but did not know him well.

"Based on what we know now, we're shocked and devastated and feel for the families of the victims," St. John-Crane told The Associated Press. "But he didn't work here. I want to make that clear. We're very frightened."

Rev. Moore said one of big messages of Allman's show was for black men to behave responsibly. "He loved his people. He was a proud black man," he said.

A video posted on YouTube shows Allman interviewing the Rev. Jesse Jackson outside a memorial for the late musician Walter Hawkins for a piece for CreaTV. In the video, Allman talks with Jackson about the positive and transformative messages of gospel music.

"I hope what he gave all of us we take out to our community and use it to better ourselves and our community," Allman said about Hawkins during the interview.

Business records show that in 2004, Allman started a youth development organization called Helping Hands Changing Hearts, which listed its location as Allman's home address. However, the IRS automatically revoked the organization's exempt status as a nonprofit for failure to file proper tax forms for three consecutive years, records showed.

"He's always had a smile on his face," said Paulette Conner, 57, a neighbor at Allman's San Jose apartment complex who said she's known him for five years. "I've never known him to have any violent tendencies. Never. Ever."

Conner said Allman occasionally griped to her and others over the years about his job, including his various shift changes and some co-workers.

Allman is known as a local fixture long involved in San Jose's black community. Before a news conference where the city's black leaders urged him to turn himself in, friends described Allman as a non-violent person not known to own guns.

"He used to do so much for the community. Something must have happened to make him flip out like this," said Pastor Oscar Dace of Bible Way Christian Center. "Everybody just can't believe that this has happened."

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Associated Press writers Brooke Donald, Terry Collins, Sudhin Thanawala, Marcus Wohlsen and photographer Paul Sakuma contributed to this report.

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