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's mummy
The location at the Valley of the Kings was significant to the New Kingdom because it is where the pharaohs of the time and some other important people to the king were buried. The idea behind burying them there was that it was supposed to be a hidden location in a remote area since tomb robbing was a constant problem during Ancient Egyptian times. Unfortunately the location was not as secret as it was hoped to be, and most of the tombs were broken into and either robbed or damaged. Tutankhamun's tomb did suffer from some tomb robbing, but overall much of it was left intact and some areas including the burial chamber appeared to be left unscathed.
A sarcophagus in the tomb's burial chamber housed three nested coffins which all depicted Tutankhamun. A small wreath of flower petals had been placed around the vulture-and-snake-symbol above the forehead of the outermost coffin. The innermost was made of solid gold and featured the mask of Tutankhamun. The linen wrappings of the mummy it enshrined were not removed for a year after its discovery. The excessive use of oils and unguents had aversely effected the corpse, making its mummification essentially a failure.