TOWN OF LIBERTY, Wis. -

A 55-year-old Lancaster man was killed when he drove an ATV off a three-foot tall retaining wall, according to a release from the Grant County Sheriff’s Office.

Deputies were called to a property on Coon Hollow Road in the town of Liberty on Thursday at 7:45 p.m. for a report of an ATV crash.

Investigators said Mark Addison drove a four-wheeler off the retaining wall, throwing him from the ATV and giving him fatal head injuries.

He was not wearing any protective gear, deputies said.

Investigators said it’s not clear why Addison drove off the wall. The incident remains under investigation.