Officers and medics responded to the scene, a Shell station and Wendy's restaurant in the 6400 block of 212th Street, at about 8:40 a.m. after receiving a report of an assault with a weapon.
Arriving there, they found two men lying on the pavement who had been shot. Both were pronounced dead at the scene, officials said.
Police said it appeared to be a random shooting, and that the shooter and victims did not know each other.
Witnesses at the scene, including a gas station employee and customers, tell KOMO News that the suspect and another man had pulled into the station in a black Cadillac to fuel up, but parked in a way that blocked other customers and their vehicles from accessing the pumps.
The witnesses said the Cadillac's music was blaring loudly, and the driver seemed confused about which side the gas cap was on.
Meanwhile, the passenger in the Cadillac got out and walked to the store, and two other men got into an argument with him outside the store about how the Cadillac was parked.
The Cadillac passenger and the two other men then got into a fistfight. When the driver of the Cadillac saw the fighting, he grabbed a gun from inside his car, ran over and shot the two men who had complained at close range.
One witness who was there pumping gas into his own car told KOMO News he couldn't believe what he was seeing and began to fear for his own life.
"I was, like, next to their car and I was kind of in shock when they started just unloading their clip," said the witness, who only wanted his first name, Alan, used. "And I was standing there like, 'Wow, is this really happening? Is this guy really shooting these guys?'"
The suspect and his passenger then quickly drove away from the scene, heading east on 212th Street.
Officers are now seeking the suspect. So far police have not released any description of the suspects or their vehicle.
Witnesses said the suspect's black Cadillac had a spare tire "donut" on the back.
This is a developing news story. More information will be posted as it becomes available.