Last Updated 9:22 p.m. ET
One of four police officers killed in an ambush at a coffee house Sunday fought with the gunman and may have wounded him before the officer died just outside the doorway, a sheriff's spokesman said.
Pierce County sheriff's spokesman Ed Troyer told reporters that investigators were asking area medical providers to report any people wounded by gunshots.
Troyer said investigators believe two of the officers were shot dead while sitting in the shop, and a third was killed after standing up. The fourth apparently struggled with the gunman out the doorway and "gave up a good fight," getting off a few shots before he was either shot there or succumbed to earlier wounds.
"We believe there was a struggle, a commotion, a fight ... that he fought the guy all the way out the door," Troyer said.
He added, "We hope that he hit him."
The officers shot were 39-year-old Sgt. Mark Renninger, 37-year-old Ronald Owens, 40-year-old Tina Griswald and 42-year-old Greg Richards.
Troyer said investigators are looking for what they describe as a person of interest in the shooting, 37-year-old Maurice Clemmons.
The gunman burst into the coffee house Sunday morning and opened fire on the officers as they sat working on their laptops, killing the three men and one woman in what Troyer described as a targeted ambush.
Troyer said officers were looking for one male suspect who fled the scene and haven't ruled out an accomplice, possibly a getaway driver.
Troyer said investigators determined that a hoax call from a person in nearby Tacoma led officers to believe the gunman was on foot and still near the coffee shop. A number of officers spent part of the afternoon carefully searching buildings close by.
Troyer said the attack was clearly targeted at the officers, not a robbery gone bad.
"This was more of an execution. Walk in with the specific mindset to shoot police officers," he said.
Troyer said the officers - all from the Lakewood Police Department - were catching up on paperwork at the beginning of their shifts when they were attacked at 8:15 a.m. Sunday.
"There were marked patrol cars outside and they were all in uniform," Troyer said.
With no known suspects, there was no indication of any connection with the Halloween night shooting of a Seattle police officer. The suspect in that shooting remains hospitalized.
"We won't know if it's a copycat effect or what it was until we get the case solved," Troyer said. "We don't even have a suspect ID right now."
Lakewood Mayor Douglas Richardson said the names of the victims would be released as soon as extended family members were notified.
In a statement, Richardson said the officers, part of the city's 100-member police force, had been with the department since it was organized five years ago. He called the crime "our most tragic event in Lakewood's 14 years as a city."
Troyer estimated that a couple of hundred officers from the Washington State Patrol and multiple surrounding police agencies in the area were at the crime scene, with some coming on their own time.
"We have no motive at all," Troyer said. "I don't think when we find out what it is, it will be anything that makes any sense or be worth it."
Two employees and a few other customers were in the shop during the attack. All are being interviewed by the Pierce County Sheriff's investigators.
"Some are in shock. They are very upset," Troyer said. "They are the ones who are going to put together for us how this happened."
The Forza Coffee Shop, part of a popular local chain, is on a side street near McChord Air Force Base in Tacoma, about 35 miles south of Seattle. The shop is in a small retail center alongside two restaurants, a cigar store and a nail salon.
Brad Carpenter, founder and owner of Forza Coffee, said his staff was OK and being interviewed by police, and that his main concern was for the families of the police officers.
"I'm a retired police officer, so this really hits close to home for me," said Carpenter, of nearby Gig Harbor.
Troyer said the Lakewood officers were two blocks outside their jurisdiction, and the coffee shop was a popular place for officers from surrounding jurisdictions to meet and share information.
Streets around the coffee shop were blocked off late Sunday morning, and a police helicopter hovered over a large crowd of investigators. TV video showed police taking possession of a pickup truck parked in a grocery store in Parkland.
"We are looking at some people. We are looking at some cars. We are looking at some residences," Troyer said.
Troyer said investigators were checking surveillance video from multiple sources, trying to identify a possible getaway car.
Dave Gabrielson, a clerk at Foot Mart about a block away from the coffee shop, told the newspaper all was quiet when he opened the store at 8 a.m. About 30 minutes later, "All of a sudden a million cops were zooming up and down the road," Gabrielson said.
He said he saw officers bring a police dog into a nearby apartment complex.
This is the second targeted police shooting in the area in the last month, reports CBS News correspondent Hattie Kauffman. Seattle police officer Timothy Brenton was shot and killed Halloween night as he was sitting in a cruiser with trainee Britt Sweeney. Sweeney was grazed in the neck.
Authorities say the man charged with that shooting also firebombed four police vehicles in October as part of a "one-man war" against law enforcement. Christopher Monfort, 41, was arrested after being wounded in a firefight with police days after the Seattle shooting. He remains hospitalized in stable condition, the hospital said Sunday.
The officers killed Sunday were a patrol squad made up of three officers and their sergeant. No threats had been made against them or other officers in the region, sheriff's officials said. Their families have been notified.
"We lost people we care about. We're working to find out who did this and deal with him." Pierce County Sheriff Paul Pastor told reporters at the scene.
Washington Gov. Chris Gregoire said she was "shocked and horrified" by the killings.
"Our police put their lives on the line every day, and tragedies like this remind us of the risks they continually take to keep our communities safe," she said in a written statement. "My heart goes out to the family, friends and co-workers of these officers, as well as the entire law enforcement community."
At Rollies Tavern near the coffee house, the plasma TVs usually tuned to football had Northwest Cable News on. Three bar patrons live next door to the coffee house.
Jerry Arnold, 45, was in bed when he was awakened by sirens. He's lived there seven years and never seen anything close to Sunday's scene.
"I hope they get them. I can't sleep until they do," he said. "Those guys could be hiding in my backyard."