Thanks LL!
None of the history I read about the circumstances made Richard III seem guilty of murder-he didn’t have any reason to fear kids from a marriage that had been declared invalid. If he did want Kate and Edward’s sons to go away for whatever reason, he could have simply bundled them up and sent them to a distant relative or royal friend far away-Spain, France, etc, and called it furthering their education or fostering-he was the king, after all-no need for murder. Maybe that is what he did, and no one thought anything of it at the time.
If they were murdered-I’m more inclined to think Henry Tudor engineered it-he had a fragile claim to the throne-through marriage rather than direct inheritance.