What happened to Raoul Wallenberg?

Due to the contraversial nature of his disappearance this may eventually end up in GD.

Going beyong wiki, what does the best evidence say about Wallenberg’s fate. Executed shortly after the war or dying insane after decades in prison or somewhere in between?

Added bonus, what is a good book to read about Wallenberg’s work during the war?

Well, at the end of the war, he was taken into custody by the Russians who thought he was a spy for the US and then ?

The Russians claimed he died of a heart attack in prison in 1947, but we’ll never know for sure. There was another Russian commission set up that said he was executed by the KGB in 1947. And, then of course, there are a lot of people who believe that he lived past that.

(Apologies for a brief hijack) When I was in Junior ROTC, our colonel gave us a name of someone he felt we would not have heard of, and would not be able to find any information about by the following day (this was before the internet was what it is). Something (probably my tendency to skip class back then) kept me from ever finding out the answer. I have tried remembering that name ever since, but all I could remember is that it reminded me of Rube Goldberg.

I do believe it was Raoul Wallenberg, so thanks for solving a long-running mystery.