The U.S. Department of Justice says an investigation found evidence that a Kentucky jail routinely uses excessive force against inmates through the use of chemical agents, restraint chairs and electronic control devices.

News outlets report a Thursday letter by the agency to the Boyd County Detention Center warns a lawsuit could be filed if conditions don’t improve within 49 days. It says the investigation found reasonable cause that jail conditions violate inmates’ Fourth, Eighth and Fourteenth Amendment rights.

State police have said a jail inmate was found dead in a restraint chair in November and five deputy jailers were charged with manslaughter.

Boyd County Jailer William Hensley took over in December and says the issues predate him. Hensley says he and county officials have made several improvements including additional training for employees.

“I know prior to December 3 the pepper spray was used quite often and so were the Tasers,” Hensley said.

Since he took office and required additional training, Hensley says deputy jailers haven’t used either and a restraint chair has only been utilized twice by order of a mental health professional.

“It’s designed to prevent self-harm, not as a punishment,” Hensley said.

He said his administration will continue to cooperate with the Justice Department investigation.