Tutankhamun's mummy
Detective Michael R. King and FBI profiler Gregory M. Cooper came together with an actual Egyptologist to form their own theory which was that Tutankhamun was murdered. With the use of forensic evidence and their extensive backgrounds in criminology, they came to the conclusion that he was likely murdered by one of his closest advisors, Ay. Ay did succeed Tutankhamun on the throne, so they used that as the motivation for the murder.
Tutankhamun
His tomb was robbed at least twice in antiquity, but based on the items taken (including perishable oils and perfumes) and the evidence of restoration of the tomb after the intrusions, it seems clear that these robberies took place within several months at most of the initial burial.