There are no surviving records of Tutankhamun's final days. What caused Tutankhamun's death has been the subject of considerable debate. Major studies have been conducted in an effort to establish the cause of death. There is some evidence, advanced by Harvard microbiologist Ralph Mitchell, that his burial may have been hurried. Mitchell reported that dark brown splotches on the decorated walls of Tutankhamun's burial chamber suggested that he had been entombed even before the paint had a chance to dry.