At 16:20 central time, a Beech V35 lost power and struck a tree and crashed one mile south of the Anoka County/Blaine Airport. The pilot and one passenger were seriously injured and one other passenger suffered minor injuries. The rear-seat passenger said they had been making left traffic for runway 35 and had been operating in the traffic pattern for 20 to 30 minutes when the engine quit. As they turned base to final the airplanes right wing hit a tree and the airplane went straight down. The passenger exited through an emergency door and noted the airplane beginning to burn. He then got the other two occupants out of the airplane. An initial examination of the engine and other airplane systems showed no anomalies.