Authorities call the attack an ambush on the officers, who were meeting in a coffee shop before their shift. At least one returned fire and may have injured the lone gunman. No one else was hurt.

The four slain officers, from left: Greg Richards, Tina Griswold, Ronald Owens and Mark Renninger. (From the Associated Press / November 29, 2009)

Four Seattle-area police officers were shot to death Sunday morning in a coffee shop in what officials called a brazen ambush by a lone gunman.

At least one officer apparently fought his way to the coffee shop door and returned fire, possibly wounding the shooter, authorities said.

The shooter is likely to seek medical treatment for a gunshot wound, officials said.

The officers, three men and a woman attached to the Lakewood Police Department, were conducting a routine pre-shift briefing over their laptops at the Forza Coffee Shop in Parkland, Wash., near McChord Air Force Base, about 35 miles south of Seattle.

"It was definitely an ambush, target situation. . . . It was not a robbery," said Pierce County Sheriff's Sgt. Ed Troyer, whose department is investigating the killings. "We have our work cut out for us."

The slain officers, who were in uniform and wearing bulletproof vests, were pronounced dead at the scene. They were identified as Sgt. Mark Renninger, 39, and Officers Ronald Owens, 37; Tina Griswold, 40; and Greg Richards, 42.

Two baristas and several other customers were not injured during the 8:15 a.m. attack. It was not known whether the gunman -- described as a scruffy-looking black man in his mid-20s to mid-30s, 5-feet-7 to 5-10, wearing a black jacket, a gray hooded sweat shirt and blue jeans -- said anything as he opened fire with a handgun and then ran out. His motive was a mystery.

"We know he left the coffee shop on foot, and after that we don't know what happened," Pierce County spokesman Hunter George said.

A possible getaway car "is one of the things we're looking into," George said.

Another Pierce County spokeswoman, Sheri Badger, said a white pickup was found abandoned not far from the scene and was impounded for investigation.

Late Sunday, Troyer said investigators were looking for a person of interest in the shooting: Maurice Clemmons, 37. The Seattle Times reported that Clemmons had a long record of violence, including at least five felony convictions in Arkansas. It said that then-Arkansas Gov. Mike Huckabee had commuted Clemmons' prison sentence nine years ago, and that Clemmons had been jailed in Washington until six days before the shooting.

The four officers "are known by everybody," Troyer said. "They've all worked in law enforcement in western Washington for their entire careers.

"It appears they were doing paperwork and getting ready for their shift to start -- going over who they would be looking for and what they would be doing during the day," he said.

Earlier, authorities offered a $10,000 reward for information, began searching for surveillance video and sent 100 or more officers and dogs throughout the surrounding area.

"We've got multiple people showing up on their days off. Every person you could think of is out here," Badger said.

Badger said officers took a person of interest into custody shortly after the shootings but had not identified the person as a suspect.

"By the way they're talking, it doesn't look like they're any more than a witness," she said.

Police also took into custody a man who called 911 and claimed to be the shooter. He was ruled out as a suspect but faces charges in connection with the false report, Badger said.

The slayings stunned a community that only recently buried another police officer, who was shot to death in his parked patrol car in Seattle. The suspect in that case was shot during his arrest and remains hospitalized.

Investigators said there had been no threats against the Lakewood Police Department or any of the officers killed Sunday. Lakewood has had its own police force for five years. (Previously it contracted with Pierce County.) It had 102 sworn officers.

"Something very terrible happened today," Pierce County Sheriff Paul Pastor told reporters. "This is an example of the danger that police officers and deputy sheriffs and state troopers face every day. The person or people who did this not only harmed us, they harmed the good that we can do in the community."

Before the shooting, Pastor had published a statement on the department's website pointing out the "uncharacteristically large" number of officers in Washington state killed recently in the line of duty. Four were killed in the 18 months before Sunday's shooting.

"Perhaps the most lasting tribute we could make and the best thing that we could do for our own safety and well-being is to find ways to make their work safer and more effective," Pastor wrote.

The previous shootings were unrelated to each other, and authorities have not connected any of them to Sunday's attack.

The most recent of the previous shootings was Oct. 31, when Seattle Police Officer Timothy Brenton was killed in his parked car and an officer trainee was slightly injured.

Police say they have linked the suspect in that case, Christopher J. Monfort, 41, to the Oct. 22 bombing and arson of a Seattle maintenance yard, which damaged four law enforcement vehicles. A note threatening to kill police officers was found at the maintenance yard.

Monfort, a former security guard, received a bachelor's degree from the University of Washington in 2008 and completed a project for the McNair Scholars Program called "The Power of Citizenship Your Government Doesn't Want You to Know About: How to Change the Inequity of the Criminal Justice System Immediately, Through Active Citizen Nullification of Laws, as a Juror."

The coffee shop where the four officers were killed is in a quiet, semi-industrial unincorporated area of Pierce County next to a Coca-Cola bottling plant.

Michael Bostwick, a retired computer worker who has his coffee every Sunday morning at a tavern nearby, said he arrived just as the first emergency vehicles showed up. He said law enforcement officers frequently have coffee at one or another of the businesses in the area, which he said is not known for serious crime.

"There haven't been any gang issues here for years, that I'm aware of. The police have had real good control of it, and have had since the early '90s," he said.

The idea that a gunman, or gunmen, is now at large is "traumatic" for the community, Bostwick said.

"It is awful. But they will get him. He picked the wrong state to do it in. We're a very well-armed state; they haven't quite taken away all of our rights yet," he said. "I can tell you that most people have probably got their weapons loaded right now. And they're waiting. Somebody will get him."

But Troyer warned citizens to be wary.

"We have somebody who shot four police officers in uniform. Don't put yourself in harm's way," he said. "Somebody that's out there and has already done that probably isn't afraid to do anything else to somebody else, and that's somebody who's very, very dangerous."

Gov. Chris Gregoire said she was "shocked and horrified" at the killings and offered the state's help in tracking down the culprits.

"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 statement.

"My heart goes out to the family, friends and co-workers of these officers, as well as the entire law enforcement community."