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.
Ay
In 2010, a team led by Zahi Hawass reported that he had died from complications caused by malaria and Köhler disease but another team from the Bernhard Nocht Institute for Tropical Medicine in Hamburg believes his death was caused by sickle cell disease. Tutankhamun could very well have died from this, combined with the infection in his knee. Ay was also buried in the tomb intended for Tutankhamun in the West Valley of the Kings (WV23), and Tutankhamun in Ay's intended tomb in the East Valley of the Kings (KV62).