Kyle Van Winkle died after a reported scuffle in the Arrowhead parking lot during Sunday's game.
The medical examiner has not determined a cause of death. Results from an autopsy are expected to take weeks to be completed.
Homicide detectives are now talking to witnesses and plan to turn the case in to prosecutors later this week.
According to police reports, the owner of a Jeep Cherokee found Van Winkle in his car just after 5 p.m. Witnesses have told police a struggle ensued and Van Winkle collapsed. He later died at a hospital.
Police say they still need to talk to more witnesses and have asked anyone who may have seen the incident to call the TIPS Hotline at 816-474-TIPS.