DENVER — An autopsy has found that a school bus driver who crashed into a pillar at the airport and died last month may have lost consciousness before the crash, The Denver Post reports.

As previously reported, the bus driver, Kari Chopper, was picking up high school football team members, who were returning home from Denver International Airport after a game in California. She drove off the road and into a pillar at about 30 miles per hour to 40 miles per hour. The speed limit on the road that the bus was traveling on is closer to about 15 miles per hour, and it is unclear why the bus was there.

The autopsy determined that Chopper had an enlarged heart and may have lost consciousness during the crash, although the autopsy report states that that “cannot be confirmed with any degree of certainty,” according to the newspaper. The autopsy also found that Chopper was overweight, and the report states that abnormal heart rhythm or a fainting episode could have preceded the accident. Toxicology tests found no signs of drug or alcohol use, The Denver Post reports.

Police did not find any mechanical problems with the bus, as previously reported, or any indication that the crash was intentional, according to the newspaper.

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