FORT WORTH, Texas — A medical examiner says a man who died in the infield during Saturday’s NASCAR race at Texas Motor Speedway shot himself in the head.

The Tarrant County medical examiner’s office on Sunday said the death of 42-year-old Kirk Franklin of Saginaw, Texas, was a suicide.

Fort Worth police have said a man who was camping in the infield died of a “self-inflicted injury” after getting into an argument with other campers. The incident happened late in the Sprint Cup race.

Texas Motor Speedway policy, in accordance with state law, bans weapons and firearms on speedway grounds.

Police representative Cpl. Tracey Knight has said alcohol may have been a factor. Knight said several people witnessed the incident, but none of them was in danger. There was no immediate word on Franklin’s connection to people in the argument.

Track spokesman Mike Zizzo say the death occurred “in or around a pickup truck” in part of the infield near the middle of the backstretch.

The Sprint Cup race was sponsored by the National Rifle Association.