Did Saruman kill Radagast?

[Alcuin]

Valandil put forward this idea in this thread:

Originally Posted by Valandil

It has always seemed ominous to me that the Elves of Rivendell could not find Radagast before the Fellowship departed... and I’ve suspected Saruman of foul play here.

The more I think about it, the more I think Valandil must be right.

Once Gandalf escaped, Radagast would soon discover Saruman’s treachery. Though he had until then been neglectful of his mission, I think this knowledge would urgently have refocused him.

On his own ground, I suspect even Radagast could be dangerous; allied with Gandalf or other members of the White Council, there is no telling what he might help them accomplish: Gandalf indicated Radagast was a shape-shifter, something I don’t believe the other Istari could do in their incarnate forms.

Saruman had to deal with Radagast after Gandalf escaped. I think he may very well have gone so far as to kill the Brown Wizard. It was just too risky for Saruman to leave him loose.