SEATTLE: A gunman killed four people at a popular Seattle cafe on Wednesday then fled to a downtown parking lot where he killed a fifth person and stole her car before shooting himself in the head as police closed in, authorities said.

The suspect identified as Ian Lee Stawicki, 40, and described as mentally disturbed, died at a hospital hours after the late-morning slayings, which police initially treated as two separate incidents.

The father of the sole surviving victim, the cafe's chef, told Reuters that police detectives had said the gunman was known to have had "psychiatric problems" and caused a disturbance at the coffee house a few days earlier.

The burst of gun violence prompted a security alert and lockdown at several Seattle schools and city-run community centres. Residents were advised to stay behind closed doors as police searched for the suspect.

Seattle Mayor Mike McGinn told a news conference that the two slayings, following a recent rash of other shootings, had shaken the city. He urged municipal leaders to "bring an end to this gun violence that the city is seeing."

Authorities had no immediate explanation for the bloodshed, which they said began when the gunman opened fire at the Cafe Racer, a coffee house in Seattle's Ravenna neighbourhood known for its live music.

Two men were killed outright, and three other people struck by gunfire were taken to Harborview Medical Center, where two of them - a man and a woman - later died of their wounds.

The suspect fled the cafe on foot and made his way a short time later to downtown Seattle, where he shot another woman dead and drove away with her sport utility vehicle, police said.

Police later found an SUV matching the description of the getaway vehicle, with a handgun visible inside, in a West Seattle neighbourhood.

The suspect had left the car, but officers who confronted him later saw him kneel down and shoot himself in the head, police said.

"The man detectives believe to be the lone suspect in 4 murders in 2 locations shot himself in the head when approached" by Seattle police, the police department said in a statement posted on Twitter, before the fifth death was announced.

Stawicki's brother, Andrew, 29, a resident of Ellensburg, Washington, told the Seattle Times that his older sibling, whom he recognized from a published photo taken from the Cafe Racer's surveillance camera, had a history of mental illness.

"It's no surprise that this happened," the younger brother was quoted as saying. "We could see this coming. Nothing good is going to come with that much anger inside you."

Stawicki was known to frequent the cafe and reportedly had quarrelled during previous visits with two of the people he shot, neighbourhood residents told local TV station KIRO-7.

The sole surviving victim was identified as Leonard Meuse, 46, the cafe chef, who was hit by at least one bullet that pierced a lung, grazed his liver and a kidney but missed his heart, his father, Raymond Meuse, told Reuters.

The gunman, he said, "was a person who has psychiatric problems and had been disruptive there (at the cafe) a few days earlier, detectives told me."