Denver airport school bus crash cause remains mystery

Police are closing their investigation into why a school bus filled with football players and coaches crashed into a pillar at Denver International Airport without being able to find a cause.

The Sept. 11 crash killed the driver, 43-year-old Kari Chopper, and injured 18 passengers from Legacy High School, who were returning from a game in California.

Sgt. Michael Farr said Wednesday that there was no mechanical problem with the bus and nothing in Chopper’s history to suggest the crash was intentional. An autopsy found that she had an enlarged heart and that she may have had a medical problem but that couldn’t be determined for sure because of the injuries to her body.

Adding to the mystery, Chopper was circling back toward the airport terminal when she crashed but no one knew why.