They did much more than steal some bitcoins according to the indictment. The investigators, in an effort to conceal their criminality and in bad faith did systematically conceal and destroy material evidence collected during their investigation. The investigators had administrator access to the Silk Road systems which they used to rob the silk road service and then framed the original owner of their admin account for the theft (and then, with another account, offered to conduct a "hit" against that admin to extract more money from DPR) in one of many (successful) extortion attempts they carried out over months-- spanning back long before the government had any idea who DPR might be (e.g. in April 2013 they believed it was "A.A."). Their unlawful actions were not limited to SR, e.g. Force ripped off a random user of the CoinMKT exchange to the tune of a quarter million dollars where he was moonlighting (against policy and in a conflict of interest) as their compliance officer. When Force's improper use of an administrative subpoena (to attempt to unblock his rightfully suspicious-flagged account) was reported to his superior by Venmo (a payment processor subsidiary of Paypal) he responded by attempting to seize Venmo's accounts.
Lets put aside for a moment Force and Bridge's roles as law enforcement and read their indictment as though they were just private individuals. Considering their access, strongly established involvement (e.g. the money trail connecting _them_ to SR appears to be much stronger than the money trail connecting Ross to SR), established pattern of fraudulent and vindictive activities including framing C.G. for the theft of bitcoin; they'd make a nice direction to throw doubt at the prosecutions claims and support of Ross' "it was someone else" argument.
Consider the counterfactual with the character portrait painted in their indictment in mind: If Force and/or Bridges had had the opportunity to take over the operation of SR (from which they could rip people off on a greater scale), would they have done so? I think the picture painted by the indictment says yes. If they had and Ross pissed them off, would they have framed him? I think the indictment says yes (or even without pissing them off: They seized MTGox's US accounts immediately after successfully getting their own funds out (to the detriment of everyone now suffering from MTGox's insolvency)). I think this is a much more powerful line of argument than "maybe magicaltux did it", at least. They destroyed evidence related to their own interactions with magicaltux (and appeared to have made a successful unlawful forfeiture against MTGox as part of their criminal activities). In the story told in the indictment, these parties had the motive, the means, and opportunity that would have permitted them to frame Ross in order to conceal their own criminality (or to protect someone else who was paying them more); and the defense was apparently prohibited from presenting this in the trial.
No doubt the prosecution did their hardest to separate out any potentially poisoned evidence, but these parties were the states only inside eyes inside silkroad. It seems unlikely to me that any of the later evidence was derived in isolation of their input, but regardless: it appears that they'd heavily spoiled the crime scene before any of the other investigators arrived.
What this actually means in terms of the actual law and procedures in the court, but I can't imagine that it would have had no effect on the jury unless they were prohibited from hearing it, nor can I really imagine them being prohibited from hearing it if it had been anything other than law enforcement agents (e.g. if it had just been other random criminals). But they were. I can't imagine why the defense didn't delay the trial so that more of this information could be presented.
This information has certainly made a number of strange things I observed make more sense.
Edit: Ah, I see Ross' attorney has made a statement:
http://freeross.org/ulbrichts-attorneys-statement-regarding-silk-road-corruption/ Seems that I called at least part of their approach, plus apparently the state used the existence of this other prosecution to suppress other evidence from being presented. Hopefully Dratel will now move to have whatever relevant filings or orders were made regarding this unsealed, so we can get a more objective view of how much this prejudiced the case.
See my above response regarding "poisoned" evidence.
Ultimately, your argument comes down to, "From reading this indictment, I think that there must be evidence that these agents planted some or all the government's evidence that was used against Ulbricht." Given that it appears that defense made that argument under seal to the judge, and the judge rejected it, I'm guessing that there was no evidence of the sort. Thus, this entire series of events with the agents is simply irrelevant and speculative: simply because these law enforcement officers essentially stole and embezzled money does not mean that Ross Ulbricht did not commit the crimes which a jury convicted him of doing.
Had the officers testified, then of course it comes in, because it's relevant to their personal credibility. But they did not (wisely) testify. Indeed, they may have been able to assert a privilege had they done so.
