MOUNT VERNON -- The suspect in a Skagit County shooting spree that stunned rural communities and claimed the life of a sheriff's deputy sat silently in a courtroom here Wednesday afternoon as a judge set bail at $5 million.

Isaac Zamora, 28, is facing six counts of murder and two counts of attempted murder. Authorities said additional charges stemming from the Tuesday rampage, which left six people dead and four wounded, are likely.

Zamora said nothing as a District Court judge reviewed the charges and assigned a public defender to the case. He winced as he was ushered from the courtroom back to the county jail.

Police disclosed Wednesday that one of the wounded victims, a 61-year-old man, was stabbed in the chest. He was being treated at St. Joseph Hospital in Bellingham, authorities said.

Most of the other victims appeared to have been shot.

"This was not a typical day anywhere" for law enforcement, said Sgt. Robert Goetz, an Everett Police spokesman assisting Skagit County authorities.

More than 100 investigators from more than dozen police agencies are helping process at least seven crime scenes over a wide area, he said.

Among the wounded was a State Patrol trooper who was grazed in the arm during a high-speed chase down southbound Interstate 5. His injuries were not considered life-threatening.

Reached at her home by telephone, Zamora's mother said Tuesday night that her son had a history of mental illness that had gone untreated despite the family's efforts.

Dennise Zamora said her son had been growing increasingly psychotic in recent days.

"We're devastated for everybody," Denise Zamora said from her home near Alger, about 10 miles north of Mount Vernon. "I'd rather it had been him or me, rather than these dear people."

The incident began at 2:19 p.m. when police were called to a disturbance in the 19500 block of Silver Creek Drive near Alger, Leary said. Troopers did not specify what kind of disturbance it was.

Sheriff's Deputy Anne Jackson, who had responded to several previous calls involving Zamora, was killed there, as was another person and two male construction workers believed to be working at the house.

Another victim appears to have been shot on the interstate, where police were processing a crime scene around an SUV that had crashed in the median near milepost 238. That's also where the trooper, who was on a motorcycle, was grazed in the arm, Leary said.

Leary reported the shooting suspect was pursued to the Kincaid Street offramp in downtown Mount Vernon. He went into the parking lot of a Skagit County sheriff's precinct and was arrested there about 4:30 p.m.

The State Patrol closed all southbound lanes of I-5 north of Burlington, backing up traffic for miles, as they appeared to be focusing on the crime scene where the motorist was shot during the chase that reached speeds in excess of 90 mph.

Officers first became concerned about the slain deputy when she did not respond to calls from the house and backup was sent for a status check.

When a backup officer arrived at the house, Jackson was found dead near another person who also had been fatally shot. Leary said two construction workers had been killed at a nearby address, and authorities think they might have been working at the address.

Officers found another person dead at a separate address.

A man who works at the Shell station in Alger, John Song, said police blocked the road outside his business after a man was shot there. Song said he didn't witness the shooting.

Police were trying to sort out details between the scenes and were unclear of the specific timeline of events.

The suspected shooter had been on a Skagit County Sheriff's Office watch list, Leary said.

"From what we were told, he was just going down the road and shooting at people," Leary said.

Authorities did not specify whether any firearms had been recovered.

Dennise Zamora said her son had been living in the woods in northern Skagit County before the shooting. His family had tried to push him into treatment for mental illness, but Isaac Zamora fought their efforts, she said.

She said the family was unable to get him institutionalized for his mental illness.

"We couldn't force him to do anything," Denise Zamora said. "There's got to be a balance so people like him can't hurt people."

Dennise Zamora said her thoughts were with the slain deputy Tuesday night.

The deputy, whom Dennise Zamora declined to identify, had been called out to the home numerous times since joining the department in 2002. She'd asked that she be called if Isaac Zamora's condition worsened.

"She's known my son on plenty of occasions," the suspect's mother said.

After learning of the shootings, Gov. Chris Gregoire directed State Patrol Chief John Batiste to assist local law enforcement in the investigation.

"Our law enforcement heroes are the first line of defense against crime and they risk their lives every day to protect others," Gregoire said in a statement. "Tonight I ask my fellow Washingtonians to pray for the friends and families who suffered such a terrible loss."