Possibly use them in sting operations of more underground sites like the silk road. Obviously as we've seen they are still going after dealers, hitmen, CP and this would be a large enough fund of coins to do that from. The only issue I see is how they would tumble and transfer them without everyone watching for transactions out of the main account.
Yep these will be watched as closely as Sathoshi's (alleged) coins.
... which will be completely useless if they use a tumbler. It's only a matter of time before feds become skilled techies. If they currently have anyone remotely capable on their staff -- and let me remind you, they somehow managed to acquire server images of Silk Road even though it was operating as a Tor hidden service, so apparently they do -- then those technically-capable staff members will strongly advise them to tumble those coins.
Which service will tumble 32 million worth of coins? And if they do them per bust then people will still see a transaction of x amount leaving their wallet.
Exactly, regardless if they tumble it, they still have to tumble it. Which creates plenty of technical and legal challenges. I personally doubt they would essentially launder their own seized money for future operations.
They aren't going to tumble all 32 million. Even 10k-20k USD worth of coins is enough to work with for most criminal cases.
The same that they do with all things they seize. It will be held for some time and then auctioned off.
I think you're right. It would take time and effort (and cash) on their part to anonymize these bitcoins, so I suspect they'll sell them at a slightly discount. I'm sure plenty of people would buy 10%-off FBI bitcoins.
I assume that most exchanges involving bitcoins are purely speculative. Given that, I don't see most buyers caring (or even knowing) whether they have an "FBI bitcoin".
They should securely erase the private keys and sell the seized equipment at auction.