The suspect was pulled over and arrested three counties away, Officer Myron Travis of the Mukilteo Police Department said.
We are sad to report 3 fatalities tonight, 1 injured and transported to Harborview, we do not know the extent of injuries #ChennaultShooting— City of Mukilteo (@CityofMukilteo) July 30, 2016
About 15-20 people were in the home at the time of the shooting, and all have been interviewed by police, he said.
The shooting took place at a gathering in a home in Chennault neighborhood, approx 15-20 people present #ChennaultShooting— City of Mukilteo (@CityofMukilteo) July 30, 2016
"Our community has suffered a great loss tonight," Mayor Jennifer Gregerson said. "There were many young people who saw and heard things that no one should ever experience."
Police did not release the names of the victims. The injured person was taken to Harborview Medical Center with unknown injuries.
The shooting happened in the Chennault neighborhood of Mukilteo, a waterfront town of about 20,000 people, 25 miles north of Seattle.
Washington State Patrol Trooper Will Finn said the male suspect was pulled over at around 2 a.m. heading south on Interstate 5 near Chehalis, about 113 miles from Mukilteo. Finn declined to release information about his identity but said troopers returned him and the vehicle he was driving to the custody of Mukilteo police.
No motive has been given for the shooting. Authorities said they planned to release more information Saturday afternoon.