"The Murder of Tutankhamen: A True Story", Bob Brier, G. P. Putnam's Sons, 1998 (New York).
This book was written even before the 2003 reappraisal of the X-rays and certainly before the 2005 CAT scans of Tut's mummy. The idea that Tut was murdered by a blow to the head has pretty much been shown to be false. The idea that Ay murdered Tut is also speculative, although it wold make sense. After all,. if Tut was murdered - and he may have been - then Ay would be a sure suspect. In fact, Mika Waltari is his 1949 novel, "The Egyptian" (still probably the best historical novel of Ancient Egypt written) made that part of his plot.
This topic is also covered in Bob's set of DVD lectures. The lectures - 48 half hour presentations - are about the entire - that's the entire - history of Egypt. They are without doubt one of the articulate, clearest, and enthusiastic lectures in any subject - probably rivaling those of Richard Feynman in his field. Makes you wish you could attended Long Island University and take some of his other courses.
Bob though has always been quick to point out that there are alternative interpretations and that theories in Egyptology are not set in stone. And many of us love Bob's books on mummies. When he got permission to an embalmed a human (dead, of course) at the University of Maryland it really did add to our knowledge of how the Egyptian process worked.