Forbes has a "blockchain" podcast called UnChained.
In the last episode of this season they talk to Kathryn Haun, Assistant US Attorney and Digital Currency Coordinator for the US Department of Justice in San Francisco. She also teaches a course about digital currencies and cyber crime at stanford.
She prosecuted Carl Mark Force IV and Sean Bridges and speaks about her experiences in this podcast.
Here's the episode link: http://pca.st/mlne
Direct MP3 Link: http://traffic.libsyn.com/unchained/Unchained_-_Episode_012_-_Federal_Prosecutor_Kathryn_Haun_On_How_Criminals_Use_Bitcoin_And_How_She_Catches_Them.mp3
Concerning trends:
Use of foreign email providers for instance in russia who won't give out data without a lot of headache, as well as encrypted messaging apps.
Tumbler comments
Some of the time, we were able to unscramble what the tumbler or mixer had done. In my opinion that was because it was early days of that technology, and I do think that now, times have changed. They've changed quickly. And so I think, going forward, tumblers and mixers are going to be a real problem for us.
The good news is that she seems to be drinking the "blockchain everything" koolaid so hopefully she'll focus on that for a while.