It happened around 8:45 Tuesday night near H and Roosevelt streets near Downtown Fresno.
Police say a 56-year-old man was riding his bicycle underneath the Highway 180 overpass. He somehow ended up in the roadway.
Officers don't know whether he was hit by a car or fell off his bike, but as he was lying there, witnesses reported seeing a dark colored mid-size pickup truck run him over and take off. That's when witnesses stopped and called 9-1-1.
A few minutes later, officers say the driver briefly returned to the scene. The driver's described as a white male with salt and pepper hair and a mustache. His passenger was also a white male.
Anyone with information is asked to call Fresno police.