In the US, it's "innocent until proven guilty".
Media is so quick to assume the person is guilty just because of an allegation.
“The arrests today show that we will take a firm stand against those who allegedly try to use virtual currencies for criminal purposes.” - Assistant Attorney General Kenneth A. Polite Jr. [My emphasis.]
There's no reason for the Justice Dept. not to take a firm stand against those who try to use virtual currencies for criminal purposes, or say that they are doing so - and, in fact, that would be rather better than taking a firm stand against those who have merely been accused of doing so. I guess that 'allegedly' was inserted here in order to forestall a claim that this statement deprived the defendants in this case of due process, if or when it comes to trial.
Actually, the 'allegedly' bit was inserted because the defendants in this case are alleged to have committed some criminal act(s). They have not been proven (whether via a trial or a plea agreement) to have done so.
The defendants may well be "guilty," or they may not. That's what the legal process (as flawed as it may be) is constituted to determine.
Forming an opinion at to whether or not anyone has committed an illegal act(s) is perfectly normal and reasonable. However, unless you're a member of a jury in a trial, your opinion generally won't affect the outcome.
All that said, defendants are "alleged" to have committed criminal act(s) until the case has been adjudicated, whether that be by trial or plea agreement.
N.B.: IANAL.