The incident happened in the parking lot outside the stadium.
An altercation started when someone left the game and found the man, who later died at an area hospital, inside their car.
Officials say the man may have owned a similar car.
Darin Snapp with the Kansas City Police Department said initial reports from the hospital showed no obvious signs of how the man died.
Three people remain in police custody.
The death comes a year to the day that Chiefs linebacker Jovan Belcher committed suicide near the team's practice facility after killing the mother of his infant daughter.
Refresh this story for more details as they are made available.