Pretty curious information... Being on witness program might be true, but I don't know how much info he has to testify against Silk Road 1 or even if he has any info at all about that.
I find it odd if he was simply released. Although it wouldn't surprise me if that was true. After all, they've arrested BurtW, amongst other stuff, so... It wouldn't be the first wierd thing they did.
There are proably a lot of people he could roll on besides Silk road 1. I am sure cops would be interested in many of his business contacts.