Two people were killed at a Caltrans facility in Rio Dell on Monday morning in what the California Highway Patrol is calling a murder-suicide.

“At this point, investigators believe that an altercation ensued between a Caltrans supervisor and another Caltrans employee over a work-related issue,” the CHP stated in a news release Monday afternoon. “The employee retrieved a handgun and fired several rounds at the supervisor, killing her, before turning the handgun on himself.”

Investigators identified Terry Allan Hayse, 57, of Rio Dell as the shooter and Annette Kaleialoha Brooks, 61, of Carlotta as the supervisor killed in the attack.

Gov. Jerry Brown ordered flags to be flown at half staff in Brooks’ memory on Monday afternoon.

“The tragic death of this dedicated public servant is a shock to the entire Caltrans family,” Brown stated. “Anne and I send our deepest sympathies to Annette’s family, friends and her colleagues during this difficult time.”

North Coast state Sen. Mike McGuire (D-Healdsburg) also released a statement on Twitter saying his thoughts are with the Caltrans Districts 1 and 4 family.

“Tragic shooting in Rio Dell today,” McGuire wrote.

The shooting took place at a Caltrans Highway Structures Paint Department on the 1400 block of Eeloa Avenue in Rio Dell just after 7 a.m. with one woman reported dead and a man in critical condition. The shooter, later identified as Hayse, was taken to Redwood Memorial Hospital in Fortuna where he was later pronounced dead, according to the CHP.

Adam Saler lives next door to the Caltrans facility and said he heard at least five gunshots following a loud argument around 7 a.m.

“I knew it was a gunshot,” Saler said in his front yard just before noon Monday. “It was weird to be that early. It’s Rio Dell so you kind of hear shots going off anyway, randomly. … Usually you don’t hear that many shots in the morning.”

Saler stepped outside an hour later and saw CHP, Humboldt County Sheriff’s Office, county District Attorney’s Office and Rio Dell Police Department investigators in front of the Caltrans building as well as a person on the ground covered with a tarp. Saler said he believed the woman killed to be a Caltrans supervisor he and his wife knew.

“I see these people every day,” Saler said.

By noon on Monday, the Caltrans entrance was still off with blocked police tape as investigators surveyed the scene. Evidence markers could be seen in front of the building near a large pool of blood. A stack of materials covered by a white tarp near an open garage bay door was splattered with blood.

CHP Sgt. Brandon Lale stated he did not know whether the gun was recovered from the scene.

Caltrans District 1 Public Information Officer Myles Cochrane said that the facility where the shooting took place is used by District 4 paint employees. District 4 is in the San Francisco Bay Area.

Caltrans Director Malcolm Dougherty issued a statement Monday morning after being notified of the shooting.

“News of this tragedy shocks and saddens everyone at Caltrans,” Dougherty said. “Our thoughts naturally are with the families. The exact details are under investigation and Caltrans is cooperating with law enforcement.”

Will Houston can be reached at 707-441-0504.