Police say two groups of people leaving a festival in Seattle's Seward Park exchanged gunfire from their vehicles before one of them caused a collision that briefly shut down Interstate 5.

Seattle police say one man was shot in the shoulder and showed up an area hospital Sunday, but it's unclear how he got there. Authorities were still searching for the other people involved.

Detective Jeff Kappel says one of the vehicles from shootout collided with another motorist on Interstate 5, causing that vehicle to flip.

Trooper Julie Judson with the Washington State Patrol tells the News Tribune ( http://bit.ly/Qqu71y) that there do not appear to be serious injuries from the collision.

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Information from: The News Tribune, http://www.thenewstribune.com