CHICAGO — More than 300 race horses allegedly owned by a top leader of Mexico's feared Zetas drug gang have been sold for $8.8 million after being seized in a June raid, US officials said Monday.

US officials allege that Miguel Angel Trevino Morales, who is believed to be in Mexico operating as the cartel's second in command, and his brothers hid millions of dollars of drug proceeds in a horse racing and breeding operation.

One of the brothers, Jose Trevino Morales, and his wife Zulema Trevino were among seven people arrested in a massive raid which also saw the seizure of the prize-winning horses.

The quarter horse racing front appears to be more than simply a shell corporation. Several of the horses have won major races, including A Dash of Sweet Heat, which sold for $1 million.

Nor were the accused making major efforts to stay under the radar -- some of the horses ran with names like Number One Cartel and Corona Coronita Cartel.

The US government still retains possession of 45 quarter horses which it plans to auction at a later date, including "Mr. Piloto" which won $1 million at Ruidoso Downs on Labor Day 2010.

"Like all criminal organizations, the Zetas are motivated by money," US attorney Robert Pitman said in a statement. "Identifying and taking their assets is an important way to lay an axe to the root of the tree."

"This investigation has helped to disrupt this alleged international drug cartel's US-based money laundering operations and demonstrates the lengths that US law enforcement will go to deprive criminal organizations of the fruits of their illegal activities," said Steve McCullough of the Internal Revenue Service.