The Brief Cobb County detainee Robert Hardy, 64, died Sunday at Kennestone Hospital after suffering a heart attack in custody. A 64-year-old detainee died at Kennestone Hospital after going into cardiac arrest while held at the Cobb County Adult Detention Center, law enforcement officials announced Monday. What we know:Cobb County Sheriff's Office deputies found detainee Robert Hardy in cardiac arrest Saturday. What we don't know:The Cobb County Medical Examiner has not yet released the official cause of death. What's next:The Cobb County Sheriff's Office is carrying out an internal review to verify that staff followed all jail protocols.