A 5-year-old Lakeland boy was killed Saturday in single-vehicle ATV crash in the Kathleen area, according to the Polk County Sheriff’s Office.

Deputies say Eli Heard was riding in the Polaris ATV, sitting in front of his father, 32-year-old Joshua Heard, wearing a soft helmet not designed for use with motorized vehicles.

Joshua Heard was operating the ATV southbound on a dirt road, according to the PCSO, when he made a U-turn, accelerated and struck a grass mound, which caused the right side front tire support arm to break. The vehicle then rolled several times, ejecting both riders.

Both were transported Lakeland Regional Health Medical Center, where the boy was declared deceased. Joshua Hard suffered possible broken ribs.

The PCSO’s investigation is ongoing.