JACKSONVILLE, Fla. -

Police in Jacksonville are asking for the public's help in finding the driver of a tractor-trailer they said struck a man in a motorized wheelchair Monday morning and didn't stop.

Police said 63-year-old Thomas Jackson was sitting in his wheelchair on the sidewalk at the intersection of Eighth and North Pearl streets on the Northside just before 11 a.m.

They said a a semitruck was traveling westbound on Eighth Street and attempted a right turn onto North Pearl Street. Police said the rear tires of the trailer being pulled by the semitruck drove over the curb and onto the sidewalk, striking Jackson and his wheelchair. Jackson was knocked from his wheelchair and suffered life-threatening injuries.

Police said the semitruck continued northbound on North Pearl Street without stopping.

The semitruck is described as a red tractor with a dirty white trailer and cursive script writing in blue or black on the rear doors of the trailer. There is also a gold color vehicle that was traveling south on North Pearl Street at the time of the crash, police said.

Traffic homicide detectives said they would like to speak to the driver of the gold vehicle, as there is reason to believe that the driver made attempts to get the driver of the semitruck to stop and may have additional information regarding the case.

Anyone who has any information in regards to the identity or location of either vehicle or driver is asked to call the Jacksonville Sheriff's Office at 904-630-0500 or Crime Stoppers at 866-845-TIPS.