They did try to entice with him with bullshit stolen credit cards. If you read carefully the first two pages, nothing was technically illegal, other than the fishy part where the defendant said he would "think about it" when offered to be paid with stolen credit cards. Had he said "No way Jose", it would have been a perfectly clean transaction, that could have happened to anyone on HN.
Still, he allegedly didn't accept the credit cards, and the detective tried to proceed with counterfeit money. In the end the defendant was charged with money laundering simply because he was selling bitcoins, which is utterly absurd. The judge was spot on to throw the case out.
I have no sympathy for crooks using bitcoins to cover their illicit actions, but I have equally no sympathy for law enforcement burning taxpayer dollars to chase ghosts.
[1] http://www.miamiherald.com/latest-news/article91701087.ece/B...(.PDF)