As further evidence that the mutation in the amyloid gene can cause Alzheimer's disease, the scientists reported they did not find the mutation in people who did not have Alzheimer's disease. Their paper will be published in Thursday's issue of the British journal Nature.
Kading says that in retaliation for Tupac's death, his manager Marion Hugh 'Suge' Knight hired rival Blood gang member Wardell 'Poochie' Fouse to kill Diddy's long-time friend Biggie Smalls for just $13,000.
He died six days later, at the age of 25, from injuries sustained in the attack. Twenty years later and no-one has yet been convicted for the murder. For all the rumours and the conspiracies, the case remains unsolved. Here are the main theories on who killed Tupac Shakur.