MILWAUKEE (CBS 58) -- An investigation is underway after an inmate at the Milwaukee County Jail was found unresponsive in his cell Thursday, March 16. 

According to the sheriff's office, the 37-year-old man was found unconscious in his bed during a scheduled medication pass around 9:12 a.m.

The Milwaukee County Medical Examiner's Office identified the man as Terrance Mack. 

Officials say jail staff and Milwaukee Fire Department officials attempted lifesaving measures, but Mack was pronounced dead at 9:49 a.m. 

The man had been in custody since Jan. 31, 2023, according to the sheriff's office.

The Waukesha County Sheriff's Department is investigating.