They have almost positively identified the agent/assassin Richard would have used...

What's that they say about Means, Motive, and Opportunity? Perhaps a better way of saying it would be who else BUT Richard would benefit by their deaths? Especially as they were under his care and protection...

Personally I still believe the discovery of two young man's skeletons built in a stairway in the White Tower is just far too much of a coincidence. Richard's supporters claim the stairway was completed two hundred years before the Princes disappeared, but I have overseen repair and maintenance on stone structures, hammering up a few treads & risers, removing a bit of rubble fill and cramming in two small corpses, and re-cementing the risers and treads is actually quite simple, and would require only a few hours if the supplies were laid up in advance.

For those who argue a natural death, two seemingly healthy young men going ill and dying at the same time in a London devoid at the time of the plague is pretty low percentage imho. Particularly because if they HAD been sick it would have been in Richard's best interest to bring in an entire bevy of physicians to attest to their illness and natural deaths, and there is no record of any such thing.

And I think the reason as to why wouldn't Richard announce their deaths is the simplest of all. He was threatened by their living existence; by some faction or other taking up the prince's cause to replace him as king. Once they were dead and gone this could never occur; let others wonder and hypothesize at length; dead Princes never replace living Kings.

Probably the silliest argument is "But no one ever accused King Richard of killing them!" That's patently ridiculous. In the age of Divine Kingship no one accused Kings of anything, period. Hell, Henry IIX was a quite publicly a homicidal maniac and no one accused him of it... that is an excellent path to ending up in the next cell over.

Jammer