A 12-year-old girl was struck and killed by an unattended SUV outside her Seattle middle school in a "tragic situation," according to police.

       The SUV rolled about 75 yards down a "slight" hill on the side of Washington Middle School and hit the student at about 1 p.m. Thursday, Seattle Police Department Patrol Operations Chief Todd Kibbee said at a news conference.

       "Preliminarily, we believe the vehicle was rolling backwards, the driver having failed to place it completely in park," Kibbee said.

       "The person who had been driving the car is being evaluated for drug and alcohol," Kibbee said, calling that standard practice.

       The school district is offering resources to the grieving students at Washington Middle School, who are in grades 6 though 8, Seattle Public Schools Superintendent Dr. Brent Jones said.

       "We are heartbroken by this tragedy," Jones said at the news conference. "We are working to provide support to the families of the students and the staff."