Richard III was appointed Protector and gained custody of Edward V and Richard of York, both of whom he put in the Tower, from whence they never emerged alive. Then he had parliament declare both bastards on the allegation that Edward IV had not properly married their mother. That left the road to the throne open to Richard, who was crowned on July 6, 1483.
Richard III reigned for a little more than two years, until August 22, 1485, when he was killed at the battle of Bosworth Field. During that entire time he had sole custody of the deposed princes, neither of whom was heard from or seen during that entire time, despite constant demands for their production and growing, highly destructive, rumors that Richard had them murdered. Indeed, the developing consensus that he had them murdered was one of the main things that destroyed his legitimacy, enabling Henry VII to overthrow him. Hence, the only logical thing for him to have done, had he been innocent of their deaths, would have been either to produce them both alive, or to produce their bodies with an adequate, legitimate explanation of why they had died. He did neither, leading to the logical conclusion that had them killed and had their bodies disposed of. I've seen no historical evidence to indicate either that the princes were alive after August 22, 1485 or that Henry VII had access to their persons before that date which would have enabled him to kill them or have them killed. Inevitably, that leaves Richard as the murderer.
Thanks for the refresher course. From looking at the skull, it looks like Richard III had a pronagthic jaw, where the lower teeth close outside the upper teeth, better known as an under bite. The more recent royals seem to have a receding lower jaw, and possibly an overbite.
Just an observation.