Many historians say the Nazi leader died in his Berlin bunker in 1945 - but Williams claims their research, looking at newly de-classified documents and forensic tests, challenges this.
"We didn't want to re-write history, but the evidence we've discovered about the escape of Adolf Hitler is just too overwhelming to ignore," he said.
Hitler allegedly lived at this residence in Argentina after World War 2"There is no forensic evidence for his, or Eva Braun's deaths, and the stories from the eyewitnesses to their continued survival in Argentina are compelling."
Grey Wolf: The Escape Of Adolf Hitler claims the Fuhrer and his mistress Eva Braun were secretly flown out of Germany in April 1945 and taken to fascist-controlled Argentina.
It is alleged Hitler lived in the country for 17 years, initially raising his two daughters, until his death in 1962.
Grey Wolf claims Hitler did not kill himself at his Berlin bunker in 1945The book also accuses US intelligence of being complicit in the scam in return for access to Nazi war technology.
"Stalin, Eisenhower and Hoover of the FBI all knew there was no proof of him dying in the bunker," Williams told Sky News.
"It's difficult to understand why so much of the already published material we present in the book has been ignored over the years."
Gerrard Williams says the 'Hitler' skull is actually that of a young womanHe added that the book's new findings prove the "Hitler" skull fragments held by the Russians are actually that of a young woman.
Williams said he and Dunstan conducted intensive field research in Argentina, including interviews with many eyewitnesses to Hitler's presence there.
"It's only now that Argentina is once more a thriving democracy that the real stories are beginning to come out," he said.
"Even so, two of our eyewitnesses received death threats from persons unknown while working with us on this book."
The film Grey Wolf is currently in production and is expected to be released in January.
taken from http://news.sky.com/home/world-news/article/16090144