The shooting, which prompted the closure of the highway in both directions, occurred shortly before 8:30 a.m. after the male officer conducted a traffic stop on I-680 near Alamo, CHP and Contra Costa County sheriff’s officials said.

Paul Fontana, acting chief of the CHP’s Golden Gate Division, identified the gravely wounded officer as Kenyon Youngstrom, a 37-year-old has been with the CHP for seven years and worked out of Martinez.

Sheriff’s spokesman Jimmy Lee said during a news conference that it was not clear what prompted the traffic stop. The sheriff’s office was assisting with the investigation.

The driver and sole occupant of the vehicle pulled a gun and opened fire when he was approached by the officer, Lee said. He also confirmed a witness account that a second officer fired at the suspect, who was fatally shot.

The suspect’s name has been released.

Sgt. Diana McDermott, a CHP spokeswoman, said she knows the injured officer personally and thanked the public for its support as his family gathered at the hospital.

“As you can imagine, this is a very difficult situation for us,” McDermott said. “We appreciate all the calls and concerns from the public. We thank you very much. It means a lot to us.”

Highway patrol officers have been in and out of the hospital throughout the day, consoling each other and occasionally conferring with hospital security and medical staff.

“We are like a family, but it’s not just us, it’s everybody. The community, the media, the public – we’re all a family and this affects all of us,” McDermott said. “Being strong for each other is very important. (The officer’s) family will be in all our prayers and thoughts.”

Contra Costa County investigators determined that a second vehicle being sought had no connection to the shooting after they interviewed its driver, Lee said.

Authorities were alerted by a 911 call from a motorist who said an officer needed help, CHP Officer John Fransen said. A second CHP officer arrived and assisted his wounded colleague.

Gene Russell told KRON-TV that he heard loud popping sounds while going southbound on I-680. He looked under the vehicle next to him and saw an officer down.

Russell said he then saw a second officer shooting at the vehicle.

“I would say he emptied his gun,” Russell said. “The traffic continued to roll. My response was, ‘I’m in a soft-top car. I need to get as far away from there as possible.'”

Most of the highway reopened to traffic in time for the evening rush hour.