Aerial shots of the motorway where police chased the gunman at high speed
A man has surrendered to police in the US state of Washington after a series of shootings left six people dead.
The killings took place at various places in the north-west of the state.
A sheriff's deputy who went to investigate an incident was among those killed; two construction workers were found shot dead nearby.
The man gave himself up at a sheriff's office in Mount Vernon after a chase along an Interstate motorway, during which a motorist was killed.
The suspect was reportedly known to authorities as "someone with a mental illness", Trooper Keith Leary told the Associated Press news agency.
Police say the deputy sheriff went to investigate reports of a disturbance at a residence in Skagit County, north of Seattle, at around 1400 (2100 GMT) on Tuesday.
When she did not return and failed to answer radio calls, the alarm was raised.
The deputy's body was found at the scene alongside a second victim.
Then the construction workers were found and another body was discovered on a street a short distance away.
Law enforcement officials managed to track the gunman and a high speed car chase ensued on the state's busiest motorway, during which the suspect is reported to have been shooting wildly.
A motorist was shot and killed on Interstate 5 before the suspect fled South at speeds of up to 90mph (145km/h) with troopers, sheriff's deputies and Mount Vernon police in pursuit.
One of the four people wounded during the shooting spree included a Washington State Patrol trooper shot while trying to chase the gunman, police said.
The dramatic pursuit ended when the gunman unexpectedly pulled into a police station in Mount Vernon and surrendered at about 1630.
Neither the victims nor the suspect have been identified.