SEATTLE - The suspect in the shooting death of a Seattle police officer was "a lone domestic terrorist" whose apartment was a virtual arsenal of bomb-making materials and weaponry, Seattle Assistant Police Chief Jim Pugel said Saturday.

There also is evidence that the suspect, Christopher M. Monfort, 41, of Tukwila may have been planning to escalate his activities in the coming days if he had not been caught, Pugel said.

Monfort was shot Friday afternoon when detectives approached him at his apartment complex for questioning about the fatal Halloween night shooting of Seattle Police Officer Timothy Brenton.

Monfort is now in serious condition in the intensive care unit at Harborview Medical Center Saturday morning, hospital spokeswoman Susan Gregg-Hanson said. He underwent hours of surgery Friday night and arrived at the hospital in critical condition with "multiple injuries."

Investigators who later searched his apartment found weapons, a huge stash of ammunition, bomb-making materials and newspaper clippings about an Oct. 22 arson that officers believe he was involved in.

Among the weapons were two long rifles, including a military-style assault rifle, Pugel said at a Saturday afternoon news conference about the case. Components for improvised explosive devices were also found.

Police evacuated part of Monfort's apartment complex Saturday evening after finding what was described as a potential hazard. Police didn't elaborate on the evacuation but allowed residents to return to their homes after about an hour.

"This man, from everything we can tell, appears to be a lone domestic terrorist," Pugel said Saturday. "At this moment, we cannot find any ties to anyone else."

But Pugel said state, federal and local law enforcement personnel are continuing their investigation, and are anxious to talk with anyone who might have helpful information about Monfort and his activities. Anyone who can help is asked to call the department's tip line at 206-233-5000, he said.

Police went to Monfort's apartment complex after detectives received a tip at about 10 or 11 a.m. Friday that someone who owned a Datsun 210 of the type police were seeking lived there.

Other residents of the apartment complex told detectives that the owner of the Datsun had kept it covered with a tarp since the night that Officer Brenton was shot.

The apartment complex manager told detectives which apartment the owner of the Datsun lived in, and police confirmed through state records that the resident was the owner of a Datsun 210. More law enforcement teams then arrived to secure the vehicle.

Christopher Monfort

At about 3 p.m., Montford came walking toward the detectives and a team of other officers who were at the scene.

"They (the detectives) engaged him in a quick question. He immediately pulled the gun, pointed it at one of the detectives, and the report is that he pulled the trigger, it did not go off," Pugel said.

"Officers drew their guns at the same time. The suspect, Mr. Montford, ran up the stairs, turned around again. And then, as he turned, with the firearm pointed at the detectives, they shot him."

Pugel said detectives found a piece of evidence at the scene of Officer Brenton's shooting that ties Monfort back to the Oct. 22 arson of four police vehicles, three police cruisers and one mobile command vehicle.

Pugel declined to specify the exact nature of the evidence, but law enforcement sources told KOMO News media partner SEATTLEPI.COM that it was an American flag found near where Brenton was shot.

According to earlier reports, investigators found a note threatening to kill officers and fliers protesting police brutality at the arson scene.

In addition, Pugel said, there have been reports of loud explosions in the area around Monfort's apartment complex in the past three months.

Timothy Brenton

Those blasts may have been experiments by Monfort and may indicate that he planned a larger-scale terrorist action, Pugel said.

He said police still want tips from people in the neighborhood who may have information or recollections about the explosions and where they occurred.

Pugel said Monfort was formerly employed as a security guard, but lost the job at some point. Detectives now are checking to see if he ever applied for a job as a police officer.

Police still have not looked at Monfort's two cars - a green Ford Crown Victoria similar to a police cruiser and another vehicle, covered by a tarp, which may be the Datsun 210 used in Officer Brenton's shooting.

Both of the vehicles have been removed from the apartment complex parking lot and taken to a secure area.

Officer Brenton was shot and killed Oct. 31 as he sat in a car with rookie Officer Britt Sweeney after a traffic stop. Sweeney was grazed in the neck.

Montfort was shot just minutes before a memorial service for Brenton ended at Seattle's KeyArena.