POLK COUNTY, Fla. (WFLA) — Police are investigating the death of a 70-year-old man who was struck by a City of Lakeland street sweeper early Thursday morning.

Authorities say the city street sweeper was cleaning North Tennessee Avenue around 4:45 a.m. when the driver, a 57-year-old man, turned right onto East Oak Street. After making the turn, the driver felt an impact.

He jumped out of the cab to check his surroundings but saw nothing. As he moved forward, he noticed a pedestrian lying on the street behind the sweeper.

The driver immediately jumped out of the cab and called 911. When first responders arrived, they determined the man was dead.

The driver of the sweeper, who has been with the City of Lakeland for 17 years, did not suffer any injuries.

So far, detectives are unsure why the pedestrian was on the road at the time of the crash. It was not immediately clear if the man’s death was caused by the street sweeper.

An investigation is ongoing.