Police are searching for a second suspect after gunfire erupted at a crowded food festival beneath Seattle’s Space Needle, leaving three people dead and four others wounded, including a young boy.
Another suspect was earlier arrested.
Investigators believe the two suspects were shooting at each other and, although one remained on the loose, assistant Seattle police chief Tyrone Davis told a news conference that there was no ongoing threat to the public.
Police did not have a description of the outstanding suspect, he said.
“We’re still trying to figure this out,” Mr Davis said.
Two people died at the scene and a third died in hospital.
They were described as two men, aged 19 and 44, and a 56-year-old woman.
The four wounded, including a two-year-old boy, were taken to hospital and were in a stable condition early on Monday, police said.
The rest of the wounded were adults.
Mr Davis could not say if any of the victims were involved in the confrontation.
The gunfire erupted at around 6pm local time on Sunday in the waning hours of the Bite of Seattle, an annual three-day festival that draws hundreds of food and retail vendors and performers.
Dozens of officers were providing security at the event and some saw one of the suspects firing, Mr Davis said.
One suspect surrendered at the scene, but the other fled.
Law enforcement searched the grounds to no avail.
A large number of police and emergency crews responded and began evacuating the area around the sprawling Seattle Centre campus.
Faith Adia Hunter said she and her friends had just got food from a crepe vendor when gunfire broke out.
Ms Hunter realised a gunman was near them.
She and others found shelter in the nearby Seattle Children’s Museum.
“We were right next to him when it started so we took off running,” Ms Hunter said.
“So we took off running too into the building with the crowd.”
In the chaos, many vendors bolted towards the exits, abandoning their food stands.
Hours afterwards, some milled outside the police tape, wondering when they would be allowed to return to collect their tents, food and cooking gear.
Roberto Ramirez, a vendor at the event, said he heard what sounded like firecrackers before people began yelling “shooter” and frantically running.
“Suddenly everything was empty,” he said.
“People were freaked out.”
After the initial panic, new guests continued to arrive unaware of what had happened and were told by police to leave, he said.
Estan Wakonabo said he and his girlfriend were at the festival waiting in line for a photo booth when he was shoved from behind and he turned to see a rush of people fleeing.
“People were hiding, were pushing, people were falling on the ground, baby strollers were falling,” Mr Wakonabo said, adding that was when he heard gunshots.
“Once I heard a ‘pop, pop, pop,’ that’s when I knew it was a shooter,” he said.
The festival started in 1982 and draws 350,000 attendees, according to its website.
