I’ve briefly touched on the whole Zetas/money laundering/horse training affair.
Latest news from the Statesman (sadly, paywalled, but there’s enough there to get the gist): Eusavio Huitron, one of the individuals previously convicted, has had his conviction reversed by the 5th Circuit.
I can’t find any other links, so I’m not clear on why his conviction was overturned. If I do turn something up, I’ll add an update here.