Tax returns - or the lack thereof. There's almost no way in the US to make more than about 10k without it being traceable.
Also I can totally be wrong about this its one of those "I' think I heard this a few times" but I think this is one of those things where the burden of proof ends up more on the side of the accused then on the gov't.
The thing is, proof beyond a reasonable doubt is not mathematical/logical proof, it's (as I recall the jury instructions I've seen on this) basically proof to a degree that a reasonably diligent person would use in their most important business dealings.
Multiple sources of evidence that point in the same direction, even when there are theoretically possible innocent explanations for all them, can still constitute "proof beyond a reasonable doubt", which is not "proof beyond any doubt".
The way I understand it, you can analyze it mathematically. Say one piece of circumstantial evidence puts the likelihood of guilt at 20%/ not guilty at 80%. Now another one has a 15/85 ratio. Take that 15% from 80%, and you now have a 68% not guilty / 32% guilty. Keep going until you have a good enough number, and you have your verdict. Now what that number should be? 90% guilty? 95%?
In my interpretation it is all about what happened and how you spin the story. We see in books and movies where someone appears to be quite guilty but then in the twist they are not or vice versa. Now, life might be messier in some sense that such is less likely in theory. But even forensic evidence can be manipulated and the science of forensic evidence does not have the same rigorous scientific underpinnings as depicted on CSI. In a digital world, a lot of things can be manipulated, and in the world of espionage probably are.
In that case, it is probably a good thing I've never been on a jury before (sat through jury duty once, never got called). I'll have to definitely keep your points in mind if I ever have to serve on one. Thanks.
They can also do it in the form of suing the assets - the money is the defendant. There's no presumption of innocence and you have to establish a preponderance of evidence that it's legit.
On the topic of tax evasion... what if they arrest somebody and find many thousands of bitcoins in their possession, but that somebody claims that they mined them themselves (and the block-chain confirms they weren't transferred)? What if they were all mined when they were basically worthless?
Would you have to pay tax only when you convert them to dollars? I mean US multinationals don't pay income tax on foreign income until they repatriate it...
Also I can totally be wrong about this its one of those "I' think I heard this a few times" but I think this is one of those things where the burden of proof ends up more on the side of the accused then on the gov't.