A 35-year-old male inmate at the Milwaukee County Jail died Friday after being found unresponsive in the jail's mental health unit, jail officials said.

The man was conscious and breathing shortly before 2 p.m., when a correctional officer called medical staff, according a news release from the Milwaukee County Sheriff's Office.

Medical staff called for an ambulance and began CPR when the man stopped breathing, but attempts to revive him were unsuccessful. He was pronounced dead shortly after 3 p.m., the release said.

The man was brought to the jail Oct. 17 by South Milwaukee police, and an autopsy will be performed, according to the release.

Investigators with the Milwaukee County District Attorney's Office responded to the jail, and an investigation into the man's death will be conducted by the Waukesha County Sheriff's Office, release said.