some say tut died as a result of an accident in part because of a problem he had with his neck and falling off a chariot. but most think this is a cover up story by those adults working with him who wanted power. Most think he still was murdered .
'After several relatively successful seasons working together, World War I brought a near halt to their work in Egypt. Yet, by the fall of 1917, Carter and his sponsor, Lord Carnarvon, began excavating in earnest in the Valley of the Kings.
Carter stated that there were several pieces of evidence - a faience cup, a piece of gold foil, and a cache of funerary items which all bore the name of Tutankhamun - already found that convinced him that the tomb of King Tut had not yet been found.1 Carter also believed that the locations of these items pointed to a specific area where they might find King Tutankhamun's tomb. Carter was determined to systematically search this area by excavating down to the bedrock.
Besides some ancient workmen's huts at the foot of the tomb of Rameses VI and 13 calcite jars at the entrance to the tomb of Merenptah, Carter did not have much to show after five years of excavating in the Valley of the Kings. Thus, Lord Carnarvon made the decision to stop the search. After a discussion with Carter, Carnarvon relented and agreed to one last season.
By November 1, 1922, Carter began his final season working in the Valley of the Kings by having his workers expose the workmen's huts at the base of the tomb of Rameses VI. After exposing and documenting the huts, Carter and his workmen began to excavate the ground beneath them.
By the fourth day of work, they had found something - a step that had been cut into the rock. Uncertainty
Work feverishly continued on the afternoon of November 4th through the following morning. By late afternoon on November 5th, 12 stairs (leading downwards) were revealed; and in front of them, stood the upper portion of a blocked entrance. Carter searched the plastered door for a name but of the seals that could be read, he found only the impressions of the royal necropolis.'
it also seems tut's tomb was broken into approx 3 times -
'Now that the door was fully exposed, they also noticed that the upper left of the doorway had been broken through, presumably by tomb robbers, and resealed. The tomb was not intact; yet the fact that the tomb had been resealed showed that the tomb had not been emptied.
On the morning of November 25th, the sealed doorway was photographed and the seals noted. Then the door was removed. A passageway emerged from the darkness, filled to the top with limestone chips. Upon closer examination, Carter could tell that tomb robbers had dug a hole through the upper left section of the passageway (the hole had been refilled in antiquity with larger, darker rocks than used for the rest of the fill).
This meant that the tomb had probably been raided twice in antiquity. The first time was within a few years of the king's burial and before there was a sealed door and fill in the passageway (scattered objects were found under the fill). The second time, the robbers had to dig through the fill and could only escape with smaller items.
http://history1900s.about.com/od/1920s/a/kingtut.htm