The Muscatine Medical Examiner’s Office is investigating the cause of death following a medical emergency at Tyson’s in Columbus Junction. According to the Louisa County Sheriff’s Office, on Thursday at 9:40 a.m. an unknown medical problem was reported and the Columbus Junction Ambulance transported a patient to Trinity Hospital in Muscatine. The patient died at the hospital. Names have not been released. An autopsy was performed at the University of Iowa Hospital in Iowa City and preliminary results indicate the patient died of natural causes.