SKAGIT COUNTY, Wash. -- A man known to have mental health problems shot eight people -- killing six, including a sheriff’s deputy -- in a shooting rampage spanning seven crime scenes in Skagit County, state troopers and local police said.

Authorities Tuesday night identified the slain deputy as Anne Jackson, 40, a patrol deputy who had been with the Skagit County Sheriff’s Office since 2002. A trooper who was shot, Troy Giddings, 42, was treated and released for a gunshot wound to the arm. The other victims were not immediately identified.

A tip line has been established for anyone who knows anything or saw anything related to the case. The number is 360-419-3257.

Details about what may have set the man off and the sequence of shootings weren’t immediately clear, but the suspect believed responsible for all the shootings is in custody, said Washington State Patrol Trooper Keith Leary in a press conference.

Police said they are interviewing the gunman, trying to figure out a motive for the shooting spree.

The 28-year-old man was released in early August after serving six months in jail, according to a statement by the state Department of Corrections. The statement said the man reported to his corrections officer twice as instructed, and a urine analysis showed no drugs or alcohol in his system. The statement did not say why he served jail time.

A woman who identified herself as the suspect’s mother said she has tried for years to get mental help for her son.

“When they’re over 18, you can’t make them go anywhere,” said Dennise Zamora. “He just turned 28.”

“Those people, those precious people and that officer,” Zamora said. “This is the truth: I love him, but I would of rather it would have been him than any of them. It’s not his fault that he is mentally ill.”

Zamora said she said she doesn’t know what might have triggered the shooting rampage.

The sheriff's deputy who was killed was responding to a disturbance call at about 2:20 p.m. at a house in the 19800 block of Silver Creek Drive. When the sheriff's deputy arrived, one person was already dead in the home, Leary said. Some time went by before the police station called the officer to do a status check. When they received no answer, police responded to the sheriff’s deputy and found him fatally shot in the head, Skagit County sheriff’s officers said.

Two construction workers were found fatally shot at a nearby home under construction. A fourth fatality was found at another home in the same area, Leary said.

At some point, a customer at a Shell gas station in Alger was also shot in the arm. A clerk at the gas station told KIRO 7 that she was in the cooler when she heard commotion outside the station. The clerk said a man was firing his gun and hit a customer.

A high-speed pursuit ensued southbound on Interstate 5 near Mount Vernon shortly after 4 p.m. Tuesday. Around mile marker 238, a motorist who was pulled over on the shoulder was also shot and killed, Leary said.

In the same area, a Washington State Patrol trooper was shot in the arm. The trooper was taken to Sedro-Woolley Hospital with non-life-threatening injuries.

The pursuit ended when the suspect drove to Mount Vernon precinct of the Skagit County Sheriff’s Office and surrendered, Leary said. A bullet hole was found in the passenger side window of the suspect's truck, reported KIRO 7 Eyewitness News.

Police said the suspect is known for having mental health issues and that he is on a Mount Vernon watch list. Police said they believe the suspect is responsible for all eight shootings.

Chopper 7 showed police and K-9 units combing the area near the motorist fatality for evidence. Police blocked off all southbound traffic on I-5 near the Bow Hill area while police investigated.

The pursuit reached speeds of 90 miles per hour.

State Patrol troopers temporarily closed all southbound lanes of I-5 north of Burlington for a period Tuesday evening, backing up traffic for miles, as they investigated that crime scene.