I think he has nothing to fear. He's been hiding for years and even this investigation in Sweden got dropped.
It's the same with His threats that he won't forgive. Nobody will fear or worry about what he's saying, because he'd publish new leaks anyway, so there's nothing more he can do.
If the investigation was orchestrated by the US, they didn't achieve much.
But the problem is, even if the case is dropped. He will still be arrested by the British. If you would remember, he even filed cases in UN, stating that he had been "arbitrarily detained" and should be allowed to walk free and compensated for his "deprivation of liberty". He won the case. But unfortunately, the ruling was not legally binding on UK that's why he will get arrested as soon as he leave the embassy.
As for the rape case, I think they just make it up so that he can be extradited to US and put on trial for releasing secret US documents.