KCI?

[don't move]

Possibly, but if K did not see the fair catch signal, or thought it was an invalid signal (which doesn't afford R protection) and hit R immediately after he caught the ball, just as the whiste blows, I am not sure you could say the ball 'is clearly dead'.
I know it's a foul, but my crew can't reach a consensus on where the rule reference is. It can't be KCI because, by definition, that can only occur 'while the ball is in flight'.
It has to be in Rule 9 somewhere...