The defeater, Henry Tudor, was crowned King Henry VI'. It was in the Tudors' interest to paint Richard as a villain. Henry VII is also a suspect. He married the princes' sister, Elizabeth of York, strengthening his claim to the throne. This could have been jeopardised if the boys had survived. It does seem unlikely that they survived beyond the end of Richard's reign without being seen. There are also other suspects including the Duke of Buckingham, once Richard's closest ally, whom he later had beheaded.
Thomas More, writing over 30 years later, stated that the princes were mothered on their uncle's orders, secretly buried 'at the stair foot', and then reburied elsewhere in the Tower. Two skeletons, identified as those of the princes, were discovered when a building in front of the White Tower was demolished in 1674. The skeletons were examined in 1933 and pronounced as belonging to two boys, aged about ten and twelve. Were these the two boys? I think that king Richard Ill killed the two boys, but then again How could a man who seems to be so fiercely loyal to his brother, kill his brother's children after his death?
Despite having eliminated the two princes from being in line for the throne, his claim to the throne was still insecure and the Princes could be a threat all the time they were alive. Richards enemies would seize on them as a leader without real power and Richard couldn't afford that. Despite the rumours and accusations of murder, Richard never attempted to prove them alive by having them seen in public nor did he open any investigation into an investigation into the matter. This to me seems very suspicious and therefore that is why I am convinced Richard Ill killed the princes in the tower.