Four police officers were shot and killed Sunday morning as they sat working on their laptops at a Washington state coffeehouse in what authorities called a targeted ambush. Pierce County Sheriff's spokesman Ed Troyer said officers were looking for one male suspect who fled on foot, but haven't ruled out an accomplice. Troyer said the four officers killed - three men and a woman from the Lakewood Police Department - were in uniform and catching up on paperwork at the beginning of their shifts when they were attacked at 8:15 a.m. Investigators believe the officers were targeted, and it was not a robbery. Troyer would not release their names. It wasn't clear whether the officers even had time to draw their weapons to return fire, Troyer said. "This was more of an execution. Walk in with the specific mindset to shoot police officers," Troyer said. There were two employees and a few other customers in the shop. 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." He could not immediately say what agency the officers were from. The Forza Coffee Shop, part of a popular local chain, is on a side street near McChord Air Force Base in Tacoma, south of Seattle. The shop is in a small retail center alongside two restaurants, a cigar store and a nail salon. "The four of them are known by everybody here," Troyer said. "We haven't got any information as to why this happened." Streets around the coffee shop were blocked off late Sunday morning, and a police helicopter hovered over a large crowd of investigators. 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. The baristas who were inside the shop are "stunned and shocked, traumatized," Troyer said. "We hopefully will have answers, but there is nothing more we can tell you," Troyer told KING-TV. "That's as cold-hearted as it is." Last month, 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 days after the Seattle shooting and remains hospitalized. Monfort remains hospitalized in stable condition, the hospital said Sunday.