The suspect in the slaying of four police officers gunned down in a coffee shop was not found Monday in the Seattle home where he was thought to have been holed up overnight, likely wounded from his bloody encounter with the officers.

Pierce County sheriff's spokesman Ed Troyer said the location of Maurice Clemmons was not known, and it's possible he still could be in the neighborhood. Troyer also said people who know Clemmons told investigators he had been shot in the torso.

"If he didn't get a ride out of there, he could still be in the area," Troyer said.

Troyer said warrants for first-degree murder have been issued against Clemmons, 37, who is accused of shooting four officers from the Tacoma suburb of Lakewood on Sunday morning as they were working in the coffee house. Pierce County, where the shootings happened, is the lead agency investigating the case.

Police surrounded the house late Sunday. Before heavily armed police officers determined shortly before dawn that Clemmons was not in the house, negotiators spent hours trying to communicate with him, using loudspeakers, explosions and even a robot sent into the house. At one point, gunshots rang through the neighborhood.

Clemmons has a long criminal history, including a long prison sentence commuted by former Arkansas Gov. Mike Huckabee nearly a decade ago, and a recent arrest for allegedly assaulting a police officer in Washington.

Authorities allege he killed Sgt. Mark Renninger, 39, and officers Ronald Owens, 37, Tina Griswold, 40, and Greg Richards, 42, as they worked on their laptop computers at the beginning of their shifts.

Clemmons is believed to have been in the area of the coffee shop around the time of the shooting, but Troyer declined to say what evidence might link him to the shooting.

Investigators say they know of no reason four gunning down the officers, but court documents indicate Clemmons is delusional and mentally unstable.

"We're going to be surprised if there is a motive worth mentioning," said Troyer, who sketched out a scene of controlled and deliberate carnage that spared the employees and other customers at the coffee shop in suburban Parkland, about 35 miles south of Seattle.

"He was very versed with the weapon," Troyer said. "This wasn't something where the windows were shot up and there bullets sprayed around the place. The bullets hit their targets."

Officer Richards' sister-in-law, Melanie Burwell, called the shooting "senseless."

"He didn't have a mean bone in his body," she said. "If there were more people in the world like Greg, things like this wouldn't happen.

Clemmons has an extensive violent criminal history from Arkansas. He was also recently charged in Washington state with assaulting a police officer, and second-degree rape of a child. Using a bail bondsman, he posted $150,000 -- only $15,000 of his own money -- and was released from jail last week.

Documents related to the pending charges in Washington state indicate a volatile personality. In one instance, he is accused of punching a sheriff's deputy in the face, The Seattle Times reported. In another, he is accused of gathering his wife and young relatives and forcing them to undress, according to a Pierce County sheriff's report.

"The whole time Clemmons kept saying things like trust him, the world is going to end soon, and that he was Jesus," the report said.

Troyer said investigators believe two of the officers were killed while sitting in the shop, and a third was shot dead after standing up. The fourth apparently "gave up a good fight."

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

In 1989, Clemmons, then 17, was convicted in Little Rock for aggravated robbery. He was paroled in 2000 after Huckabee commuted a 95-year prison sentence.

Huckabee, who was criticized during his run for the Republican presidential nomination in 2008 for granting many clemencies and commutations, cited Clemmons' youth. Clemmons later violated his parole, was returned to prison and released in 2004.

On Sunday, Huckabee issued this statement on his Web site: "Should he 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."

It was the second deadly ambush of police in the Seattle area in recent weeks, but the two cases aren't related.

Authorities say a man killed a Seattle police officer on Halloween night and 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.

The officers killed Sunday had received no threats, Troyer said.

"We won't know if it's a copycat effect or what it was until we get the case solved," he said.

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Contributing to this report were Associated Press writers Gene Johnson in Seattle, Rachel La Corte in Tacoma, George Tibbits in Seattle, Jill Zeman Bleed in Little Rock, Ark., and photographers Elaine Thompson in Seattle and Ted S. Warren in Parkland.