They didn't prove beyond a reasonable shadow of a doubt that he was at Sobibor, did they? The only evidence was the ID card which the FBI thought was a forgery. The Soviets were known for going after Ukrainians who fought against them. If the case can't be proved, then how can they say he was definitely at Sobibor and other camps? The main suspicion was that he had had an SS tattoo removed.. but could he have been a fighter in the Ukrainian Nazi -organized army?
U.S. confirms ISIS computer expert killed in air strike (Reuters)
from the article: John Demjanjuk dies at 91, taking his secret to the grave