A disgruntled worker opened fire on Wednesday at a Northern California cement plant and quarry, killing two people and injuring six, police said.

The gunman, identified as Shareef Allman, was also suspected of shooting a woman contract worker for Hewlett Packard (HPQ.N) during an attempted carjacking a short time later, Santa Clara County Sheriff's spokesman Sgt. Jose Cardoza said.

Witnesses told detectives that authorities were looking for a man matching Allman's description who ran from the second shooting, Cardoza said.

We believe him to still be in the area. Several tactical teams are conducting yard-to-yard searches, he said.

Witnesses told police that Allman had arrived at a safety meeting at the Lehigh Southwest Cement Permanente Plant in Cupertino at about 4:30 a.m. armed with a handgun and rifle, and opened fire on his co-workers, Cardoza said.

Witnesses and victims said Allman, in his 40s, shot eight people within two minutes before fleeing in a dark colored vehicle, Cardoza said.

He was unhappy and disgruntled, according to witnesses and victims, he said. We don't know if it was work or family issues.

The cement plant is part of Germany's HeidelbergCement AG (HEIG.DE), the world's No. 3 construction materials group.

A spokesman for the plant declined to comment, saying the company would issue a statement later on Wednesday.

Today is a somber day. Our close-knit community was violently attacked, and we will continue to feel the shocks of this violence for some time, U.S. Representative Michael Honda said in a statement. His district includes Cupertino.

One of the victims from the cement plant shooting was treated and released from a local hospital. The conditions of the other five people were not immediately available.

The woman shot in the attempted carjacking, whose name was not released, was in fair condition at Santa Clara Valley Medical Center.

A spokesman for HP said that its campus, near where the attempted carjacking took place, had been closed because of the shooting and the company was working with local authorities.

The spokesman confirmed that she was in safe, stable and noncritical condition.