A manhunt is underway after a Cupertino, Calif., shooting spree left three dead and seven wounded.

Shareef Allman, 47, is suspected of opening fire at a Northern California limestone quarry and shooting and injuring a woman during a failed carjacking attempt shortly afterward. Allman was a heavy equipment operator at the Permanente Quarry, and freelanced as a public television producer and host.

Earlier reports had said that Allman had killed two people, but local news outlets are now reporting that three are dead.

Santa Clara County sheriff's Lt. Rick Sung told a CBS News affiliate that Allman had been at a routine safety meeting at the quarry when he left in anger at around 4:30 a.m. He returned shorty afterward with a handgun and rifle and opened fire, Sung said.

Allman remains armed and dangerous, Santa Clara County sheriff's Sgt. Jose Cardoza warned local residents. Because many children were already on their way to school when the incident was reported, some schools have remained in session with their buildings on lockdown, while at least one -- Laurelwood Elementary School -- was evacuated at 7:45 a.m.

Allman has been described by multiple media outlets as a disgruntled employee. And while the gunman was reportedly upset about having his shift changed from day to night, he does not appear to fit the typical profile of those associated with workplace violence.

Those who know Allman are shocked by his actions, and baffled about a possible motive.

He was a mediator. He's just a person that would try to resolve conflict. I just can't believe it, Suzanne St. John-Crane, executive director for CreaTV in San Jose, told the Mercury News. Allman had previously produced a show called Real 2 Real for CreaTV, which St. John-Crane said was spreading the word on non-violence.

In another interview with The Associated Press, St. John-Crane distanced herself somewhat. Based on what we know now, we're shocked and devastated and feel for the families of the victims, she said. But he didn't work here. I want to make that clear. We're very frightened.

(A CreaTV video of Allman interviewing Rev. Jesse Jackson was initially published with the Mercury News article, but has since been removed by the user. Another video of the interview found on YouTube is embedded at the bottom of this article.)

It makes no sense, Allman's neighbor, Albert Salazar, told the Mercury News. Nobody can understand what happened. He must have snapped. I couldn't believe it when I heard it was him this morning.

A woman who asked to remain anonymous told KCBS radio that her father was the lead employee on the night shift at Permanente Quarry, and was present when the shooting began.

She said her father called his family around 4:30 a.m. to say something was happening and not to pick him up, and called again just after 6 a.m. to say he was unhurt but was hiding. He was reunited with his family around 10 a.m.

Rose Douglas, a neighbor of Allman's apartment complex in San Jose, told Mercury News that Allman had been upset recently because he had been moved from the day shift to the night shift, as this meant less time for him to spend with his daughter.

Allman wrote a book called Amazing Grace, which addressed the issue of domestic violence against women. He discussed the book in a videotaped interview with CreaTV:

It's fiction but deals with people I've met throughout my life, Allman said in the interview. I'm a father and raised a daughter from birth, and growing up in that type of environment and seen men abuse women, I said I can do something as an individual to make a difference.

Below is a video of Allman interviewing Rev. Jesse Jackson for his show on CreaTV:

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