A man is dead after he collapsed underneath a bus and was run over Wednesday morning in Aurora, according to the Aurora Police Department.

Police said the man was found lying in the road suffering from traumatic injuries just before 6:30 a.m. near the intersection of East Colfax Avenue and North Havana Street. He was pronounced dead at the scene.

No vehicle was at the scene but, by interviewing witnesses, police learned the man had been hit by a bus with the Regional Transportation District.

Nearby surveillance footage showed the man was riding on the bus and exited using the rear doors. After exiting the bus, the man apparently suffered a medical incident and collapsed to the ground, falling under the bus, police said.

The bus driver, seemingly unaware that the man was underneath the bus, drove away, running the man over. The bus driver continued their route and was later tracked down to Union Station in Denver.

Police said they found physical evidence of the fatal incident after tracking down the bus. Though police do not believe the bus driver was under the influence of drugs or alcohol, the driver agreed to a blood test to rule out any impairments.

The investigation into the incident is ongoing. Anyone who witnessed or has footage of what happened is asked to call the Aurora Police Traffic Section at 303-739-6000. To be anonymous, tipsters can call Metro Denver Crime Stoppers at 720-913-7867.

Eastbound lanes of East Colfax Avenue were closed Wednesday morning between Geneva and Havana streets while investigators processed the scene.

The Arapahoe County Coroner’s Office will release the victim’s identity and official cause of death once his family has been notified.