United States police have named the lone gunman believed to have shot four police officers dead near an air force base in Washington State.
The BBC reports that police named Maurice Clemmons, 37, as a "person of interest" in the case.
According to reports, Clemmons has a long criminal history, including five felony convictions in Arkansas and several felony charges in Washington.
Officials said the gunman walked into a cafe in Parkland, near the McChord Air Force Base about 65km south of Seattle, and opened fire.
The cafe is a well-known meeting place for police, who gather there to exchange information on suspects.
The officers, three men and a woman, had been working on their laptops in the coffee shop before starting their shifts on Sunday morning when the attack happened.
All were in uniform and their patrol cars were parked outside.
A spokesperson for the Pierce County sheriff's department, Ed Troyer, said the officers, from nearby Lakewood Police Department, were all married with children.
Mr Troyer said they had been specifically targeted, noting that staff and customers at the coffee shop had not been shot at.
"This was more of an execution. Walk in with the specific mindset to shoot police officers," he said.
Theron Zahn, of KOMO-TV, told the BBC a huge police operation involving hundreds of officers was under way.
"Police helicopters are in the air using their infra-red cameras for anyone who may be hiding nearby. It is a massive manhunt."
Police are offering a $US10,000 reward for information leading to the arrest of the gunman.
Officials at the air force base say security has been increased at the gate.
