Sioux Falls police are investigating a fatal overnight crash that claimed the life of a teenage driver. The single-vehicle accident occurred near West 12th Street and South Grange Avenue early Sunday morning. Emergency crews responded to the wreck shortly before 3:00 a.m. on September 20, 2026.
First responders arrived at the scene to find a severely damaged 2013 Mazda 3. The car had been traveling eastbound on West 12th Street prior to the collision. Officers quickly secured the area to evaluate the driver and manage traffic.

Investigators determined that the driver lost control while attempting to maneuver through a curve in the road. The Mazda veered off the street and flipped over. The rolling car then slammed into a solid concrete structure along the roadway.
The driver was identified as 19-year-old Sioux Falls resident Johnathine Gunn. Gunn was driving alone at the time of the incident. No other vehicles or pedestrians were involved in the crash.
Paramedics treated Gunn at the site before transporting him to a local hospital for urgent care. Despite emergency life-saving efforts by medical personnel, Gunn succumbed to his injuries at the facility.
Traffic investigators are working to reconstruct the events leading up to the collision. Early findings suggest that excessive speed was a likely factor in the car leaving the roadway. The physical evidence at the curve supports theories of high speed before the impact.
Toxicology results and official reports remain pending as the investigation moves forward. Police have not confirmed whether drugs or alcohol contributed to the crash. Further details will be released as crash reconstruction officers complete their report.

