We don't know when and how Hitler died.
As you know it is the Soviets that invaded Berlin and proceeded to tell numerous and contradicting lies about Hitler's death, including how he shot himself and they got his body and autopsied him, but then he actually died of poison and was burned in the crematorium, but actually he was burned with petrol outside, and then the soviets destroyed the body, except they actually got a jaw and the skull, but actually it wasn't true because the KGB destroyed his remains in 1970, and then the skull was exposed in the archives until the year 2000, etc.
Nowadays people that hate him love the story about him killing himself since it's a loser's death, and it's more comforting than talking about how decades after the war the CIA was still paying and receiving reports from agents and rats in South America concerning his potential whereabouts.
The only reason I believe he's dead is because otherwise he'd be 135 years old.
Hitler's death is not the biggest lie of WWII, but it is one of them.