PORTLAND, Ore.—Investigators have found no evidence that terrorism, politics or any bias motivated the rampage of a 64-year-old Oregon man who witnesses said repeatedly drove into people along streets and sidewalks in Portland, killing a 77-year-old woman and injuring nine other people, police said. Police identified the driver as Paul Rivas of Oregon City. He was booked into the Multnomah County Detention Center on initial charges of second-degree murder, assault and failure to perform the duties of a driver, the Portland Police Bureau said in a news release. Rivas is accused of striking the woman, who was dragged a short distance beneath the wheels of a small SUV, and then continuing to drive, hitting other people and vehicles. After the driver fled on foot, neighbors surrounded him until police arrived. The Oregon State Medical Examiner determined that Jean Gerich died of blunt force trauma and ruled her death a homicide, …