"They can't walk up with duffel bags of money and continue with their business," Arnold said. "They have to find creative ways to convert that money into pesos and launder it so it doesn't look like illegal proceeds."

All seven of the defendants were due in federal court in Los Angeles on Monday afternoon.

A message was left for Zhou's attorney, David Elden. Flores Rivera had no attorney listed as of Monday afternoon, ICE officials said.

If convicted of evading federal reporting requirements, the defendants could face up to five years in prison. The money laundering charge can carry a sentence of up to 20 years.

The investigation started in November 2010 following a money laundering probe at Los Angeles-area toy wholesaler Angel Toy. That company's two top executives were sentenced earlier this year to more than three years in prison after pleading guilty to conspiracy to structure currency transactions.