The four Lakewood, Wash., police officers who were shot to death Sunday in a suburban coffee shop are, from left: Greg Richards, 42, Tina Griswold, 40, Ronald Owens, 37, and Sgt. Mark Renninger, 39. (City of Lakewood/Associated Press)Hundreds of police officers, some using dogs, are searching around Seattle for a man sought in the slaying of four police officers near Tacoma, Wash., on Sunday.

A special tactics police team stormed a Seattle house on Monday after negotiators spent the night trying to communicate with Maurice Clemmons, 37, who was thought to have been in the house. The officers discovered he wasn't there.

While Clemmons is still unaccounted for, police said they know he is wounded.

Police cars block access to the Leschi neighborhood of Seattle early Monday as they hunt for a suspect in the slaying of four police officers gunned down in a suburban coffee shop. (Elaine Thompson/Associated Press)Ed Troyer, a spokesman for the Pierce County sheriff, said people who know Clemmons told police he had been shot in the torso.

Clemmons is wanted in connection with the killing of four uniformed officers in the Pierce County community of Lakewood. The three men and one woman were about to start their day shift in the community near Tacoma, south of Seattle, and were sitting at laptop computers in a Forza Coffee Co. store when a man entered and opened fire on them with a handgun, officials said.

The slain officers were identified as Greg Richards, 42, Tina Griswold, 40, Ronald Owens, 37, and Sgt. Mark Renninger, 39.

Troyer told a regional newspaper: "It was just a flat-out ambush. … This was an execution, no doubt."

Police are searching for Maurice Clemmons, 37, in connection with the killing of four police officers. (Pierce County Sheriff's Department/Associated Press)Troyer said investigators believe two of the officers were killed while sitting in the coffee shop and the third was shot dead after standing up. The fourth apparently "gave up a good fight," he said.

"We believe there was a struggle, a commotion, a fight … that he fought the guy all the way out the door."

Troyer said warrants for first-degree murder have been issued against Clemmons and authorities have offered a $125,000 US reward for information leading to his arrest.

Going to shoot police: suspect

Police said they don't know what prompted him to shoot the officers, while sparing employees and other customers in the shop.

Troyer told a Tacoma newspaper that Clemmons "made comments the night before to people that he was going to shoot police and watch the news."

Clemmons's criminal record includes a 95-year prison sentence for robbery, imposed in 1989, that was commuted by former Arkansas governor Mike Huckabee in 2000.

He was recently arrested for allegedly assaulting a police officer in Washington state and was released from jail last week after a $150,000 US bond was posted by a bail bondsman.

In a statement posted on his website Sunday, Huckabee pointed the finger of blame at the justice system.

Huckabee blames system failures

"Should he [Clemmons] be found to be responsible for this horrible tragedy, it will be the result of a series of failures in the criminal justice system in both Arkansas and Washington state," he said.

Huckabee said after Clemmons had his sentence commuted and was granted parole, he later violated his parole and continued his criminal behaviour, but neither state acted to return him to prison and keep him there.

"If I could have known nine years ago and could have looked into the future, would I have acted favourably upon the parole board's recommendation? Of course not," Huckabee told Fox News Radio on Monday.

Clemmons was among 1,033 people who were pardoned or had their sentences reduced during Huckabee's 10 1/2 years as governor — a number far greater than his three predecessors combined.

'Dangerous' people let out

Pulaski County Prosecutor Larry Jegley, whose office opposed Clemmons' parole in 2000 and 2004, said Huckabee created a flaw in the Arkansas justice system by freeing the number of prisoners he did.

"[Clemmons] should have stayed locked up like the jury wanted him and we wouldn't even be having this discussion," Jegley said.

"I just have been figuratively holding my breath and hoping something like this wouldn't happen. I just think that a lot of the people that were subjects of clemency during that period of time were some very dangerous people who didn't need to be let out."

With files from The Associated Press