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.
Smenkhkare
In support of Ankhesenamun, is the idea that Tutankhamun 'lie in state' for some time. The Hittite sources indicate he died in the fall. Of course the Hittite sources may not be true, but then carvings in tomb's back up the Hittite sources. However, a cornflower pectoral indicates he was not buried until April or May. As such, there may have been time for letter writing and travel. Ankhesenamun is made more plausible if she had the backing of Ay, or Horemheb, or both. Against her is the simpler explanation that the delay in burial was the result of his unexpected death and unfinished tomb.