JACKSONVILLE, Fla. -

A man riding in the back of a pickup truck early Friday morning fell out and suffered life-threatening injuries. Now Jacksonville police are looking for the driver.

Police said Christopher Muir and several friends left the Jacksonville Landing about 2 a.m. and were riding in the back of the black truck when he fell out at Newnan Street and Independent Drive.

Police said the woman who was driving left the scene before being interviewed by investigators.

Anyone who has any information about her identity or whereabouts is asked to call the Jacksonville Sheriff's Office at 904-630-0500 or Crime Stoppers at 866-845-TIPS.