A fifty-year-old Chattooga County man died in the Walker County Jail on Friday morning.  Walker County Sheriff Steve Wilson said that Christopher Jason Callahan of Summerville was transported to the hospital after an unspecified medical emergency.  Officers and emergency medical workers performed CPR and other life-saving measures at the jail. The inmate was transported to the hospital and pronounce dead this morning around 2 AM, according to Sheriff Wilson. The body has been taken to the GBI lab in Decatur for an autopsy.