I'm pretty sure people don't need to be present to be charged with a crime.
Or are you saying that if I killed someone then skipped the country I couldn't be charged with murder ? even if I admitted to it ?
And the linguistics are quite important as generally, you can't extradite someone for 'questioning' (and to be honest, unless something has changed, I don't think he's even been accused of the crime, at the moment he is an interested party that is wanted for questioning, which couldn't be done in the month he was there waiting for them to question for some reason (apparently the police officer was sick or something) and when asked if he could leave and given permission by the prosecutor, found it couldn't be done by video (Scotland yard or the Swedish embassy) after the prosecutor changed his mind the instant (well, within hours) he left the country, but for some reason he had to travel back to Sweden for it. (even though it has since been shown that it's actually quite common to be questioned remotely by video hookup for this sort of thing)