Darlington City Fire Chief Jim Stone will retire at the end of July.
He made the announcement Tuesday afternoon amid a state police investigation into allegations of Stone's improper use of an inmate. No further details have been released.
He has been on suspension since last week.
State police are expected to wrap up the investigation in the coming days.
Stone has been the fire chief of Darlington for 50 years and is credited with helping to modernize the department and improve its relations with the community.
Chief Stone has agreed to talk with NewsChannel 15 later this week.