Authorities say 22 people are being charged in an international money laundering case that funneled cash to drug trafficking cartels through Miami-based businesses.

Miami-Dade State Attorney Katherine Fernandez Rundle said Thursday the case is a joint investigation with federal Homeland Security Department officials. Authorities say the undercover operation involved about $1 million a month in drug money from throughout North America.

The charges are mostly against the illicit money couriers working for Colombian and Mexican cartels trying to get U.S. drug-profit dollars converted into pesos they can use. No business owners were charged but Rundle says they should be on notice when handling suspicious transactions.

The Miami-area businesses are mostly involved in the South American electronics export trade.

Authorities also seized about $1 million in cash during the investigation.