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.