Litvinenko is an evil person who is falsely advertisized as an ex-KGB spy. He was actually a law-enforcement officer in charge to counter ethnic gangs in Moscow. He was a corrupted officer, allied with Boris Berezovski - a known Soros’s proxy and a part of liberal anti-Putin opposition. Litvinenko used his position to push muslim gangs he was intended to counter against Berezovski’s business adversaries. Both had ties to muslim terrorists in Chechnya.
As soon as a couple departed for London, Litvinenko turned into a costly exhausted asset for Berezovski.
An idea of a hit by Kremlin on him sound unrealistic.
To me it has three realistic versions: suicide, accident while handling hazmat, a hit by Berezovski-Soros (to get rid of useless idiot and use it in information war on Russians).
I posted to this thread 6 years ago. Try to stay current.