Answer
Ivan Mykolaiovych Demjanjuk, known as John Demjanjuk, was a Ukrainian-American accused of being the Nazi death camp guard known as "Ivan the Terrible." Although he was initially convicted, his convictions were overturned due to reasonable doubt and lack of conclusive evidence. Demjanjuk's case sparked controversy and raised questions about the reliability of eyewitness testimonies and the challenges of proving guilt in historical war crimes cases.