SAN DIEGO -- Two brothers and a third man are in federal custody Friday on suspicion of conspiring to help thousands of illegal immigrants enter the United States west of the Otay Mesa border crossing, authorities said.

Maurilio Mosley, 27, of Chula Vista, was the ringleader on the U.S. side, while his brother -- Erik Mosley, 24, of Tijuana -- ran things on the Mexican side, according to a statement from U.S. Immigration and Customs Enforcement. George Sandoval, 42, of San Ysidro allegedly acted as a driver and recruiter.

Their arrests Tuesday were the result of a yearlong investigation by both ICE and U.S. Customs and Border Protection. The smuggling operation, which involved cutting holes in border fencing, went on over the past several years, according to the agencies.

Agents said they seized evidence from Mosley's home and business in National City, including five vehicles, nearly $18,000, numerous alien smuggling ledgers and nine counterfeit $100 bills.

All three men appeared in federal court Thursday in San Diego to be charged of conspiracy and human smuggling for financial gain. The human smuggling charge carries a maximum penalty of 10 years in prison.