SHEBOYGAN, Wis. (CBS 58) -- An investigation is underway after inmate at the Sheboygan County Sheriff's Office Detention Center died while in custody. 

Officials say a security check was being performed Sunday, Sept. 14 when a correctional officer observed an inmate -- identified as 65-year-old Pao Lee -- unresponsive in the shower. Lifesaving measures were taken but Lee died. 

Pao Lee was the suspect charged in the shooting, Sept. 5, at a family-run business on S. Business Dr. in Sheboygan that left a 2-year-old toddler and a 56-year-old injured. 

The Sheboygan County Medical Examiner was contacted, along with the Fond du Lac County Sheriff’s Office, to conduct a thorough, transparent, external investigation of the circumstances surrounding the incident.