I believe VJ was a government mole on the Silk Road. If the (US) Government is after you, there is no place to hide. They'll literally stop at nothing and spare no expense to take down their mark.
I was actually surprised it took them so long to arrest Ross. They had direct access to DPR on pidgin, so why not deploy a zero-day exploit and take over his machine? They had no moral qualms about exploiting a javascript vulnerability on Tormail, so why not use a similar strategy against DPR? Half a dozen vulnerabilities are found and fixed on Firefox with every release, so it couldn't have been that hard, especially considering neither Ross nor Variety Jones were using Ubuntu with a standard install of the Tor Browser Bundle instead of a privacy oriented distro like Tails or Whonix.
most logical answer however...............
I have distribution cases.... of a schedule 1.... and they dont typically hold out on bringing everything to light in a case.... granted this is a extreme circumstance and alot of other rules have already been broken etc etc........
but I feel like if it were that easy of an answer...there would have been some indication some shred of evidence that would have made there case that much stronger if they outed vj as one of there own..... but they dident
you know? thats where I get caught up in that mole shit........
shit VJ could be fuggin Snowden....
lulz