Authorities in Ashland County are investigating three apparent opioid overdoses in the county jail.

In a news release, Sheriff Mick Brennan said two inmates were taken to Memorial Medical Center by Ashland Fire Department ambulance Jan. 9 and a third was taken Jan. 11, all displaying symptoms of overdose. All three were later returned to the jail.

All three were housed within the same cell block, Brennan said. It's believed they used drugs smuggled in by a fourth inmate.

Subsequent searches by correctional officers assisted by K9 units from the Ashland Police Department and the Bayfield County Sheriff's Office turned up no further contraband, Brennan said.