Prosecutors are set to open their case against a man accused of buying racehorses to hide illegal drug profits for a powerful cartel.

The case centers on Jose Trevino Morales, a brother of two top leaders of the Zetas. The Mexican group has become one of the biggest, most versatile and most violent criminal organizations in the world.

Prosecutors say Morales disguised drug money through the purchase of racehorses at a ranch in Oklahoma. He has been charged with conspiracy in federal court in Texas.

Morales' wife and daughter have pleaded guilty to lesser charges. His brothers remain at large. The horses have been auctioned by the government.

Lawyers for Morales have filed documents suggesting they will offer a contrasting portrait of his equestrian business dealings.