Nicaraguan authorities are investigating what they call a vast network of drug criminals behind a seizure of $9.2 million in vans driven by people pretending to be part of a Mexican television news crew.

National Police's spokesman Fernando Borge says the destination of the money for which 18 people have been detained was Costa Rica. He says it was a payment for a load of drugs.

Borge told The Associated Press Monday that a former police agent heard in Honduras a conversation from those now detained of their plans to drive through Nicaragua with the money. He said the man alerted authorities in Managua.

Initially, authorities had said they found $7 million in smuggled cash, but on Monday they said it was more money than they first thought.