POLK COUNTY, FL (WFLA) — The Polk County Sheriff’s Office is looking to the public for help in finding out more information on a single-car crash that killed four people in Frostproof on Sunday evening. PCSO announced Monday afternoon the driver, 29-year-old Reginald Burnett Jr. had succumbed to his injuries.

Deputies say Burnett, of Avon Park, was driving a 2015 black four-door Dodge car southbound on U.S. 27 between CR 630A and U.S. 98 in Frostproof with three friends in the car around 10:15 p.m. Sunday. For unknown reasons, Burnett lost control of the car, left the roadway, struck a concrete culvert in front of 8434 U.S. Highway 27, and came to rest in a drainage ditch. It is unknown where the group was heading to or from at the time of the crash.

Two passengers, 38-year-old Doyle Lane Jr. of Frostproof and 28-year-old Ryan Dawson of Eustic, were found dead at the scene. Burnett and the third passenger, 33-year-old Micah Watson of Frostproof, were airlifted to Lakeland Regional Health Center. Watson later died from his injuries. Deputies say none of the car’s occupants were wearing seatbelts. Deputies are looking into speed as being a factor in the crash; the investigation is ongoing.

After interviewing potential witnesses, deputies say another vehicle was near the scene at the time of the crash and are looking to speak with that car’s occupants. They are looking for a 90’s model black Honda with a possible light-colored left front fender. The car would have been heading south on U.S. 27. Anyone with information is asked to call Deputy Sheriff Johnnie Wombles at 863-297-1109.MORE STORIES FROM WFLA.COM: