The Tarrant County medical examiner's office on Sunday said the death of 42-year-old Kirk Franklin of Saginaw 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.
Police spokeswoman Cpl. Tracey Knight has said alcohol may have been a factor. Knight said several people witnessed the incident, but nobody was in danger.
Track spokesman Mike Zizzo says the death occurred "in or around a pickup truck" in part of the infield near the middle of the backstretch.
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