A South Florida money-laundering network secretly transferred more than $30 million in illegal Medicare profits through a remittance firm with shell companies in not only Canada and Trinidad, but also in Mexico, according to court records filed Monday.

Evidence of the widening network into Mexico surfaced in the federal plea agreement of a one-time Miami medical equipment provider who pleaded guilty Friday to his role in the money-laudering conspiracy.

Kirian Vega, 35, who owned Ozain Pharmacy in another person’s name, billed more than $600,000 in false claims to the taxpayer-funded Medicare program and received about $400,000.

According to the plea agreement, Vega admitted he used a Florida check-cashing store to launder $124,000 of the tainted proceeds in 2009 through the shell companies of the offshore remittance company, Caribbean Transfers.

Court documents show that money was wired to Turismo dos Polos in Mexico, which transferred a portion — $45,000 — to another shell company, Communications Sophie, in Trinidad. That money was then sent to an unidentified travel agency in Cuba, records show.

Last month, Caribbean Transfers was accused in an indictment of financing the complex money-laundering ring that moved millions in stolen Medicare money, mostly from South Florida, through shell companies in Canada and Trinidad and finally into Cuba’s banking system.

That revelation came to light in the case of a now-convicted check-cashing store owner who was first believed to be at the center of the federal case. It marked the first time that investigators traced tainted Medicare proceeds to Cuba’s state-controlled bank.

Caribbean Transfers appears to have played the dominant role in the unprecedented money-laundering scheme.

In October, prosecutors filed conspiracy charges against the founder of the Caribbean-based company, Jorge Emilio Perez, who is believed to be hiding in the Dominican Republic.

Also charged: Vega and Felipe Ruiz, 38, one-time operator of two Miami medical equipment businesses under others’ names. Ruiz was charged with laundering at least $1.2 million through the check-cashing store and remittance company.

The information about Caribbean Transfers, which prosecutors say is licensed by the Cuban government, was disclosed during Ruiz’s bond hearing last month. Ruiz, a Cuban-born U.S. citizen, was denied bail because a judge found he might flee to Cuba or another country.

In June, the U.S. attorney’s office in Miami made national headlines when prosecutors charged Oscar L. Sanchez, owner of the Naples check-cashing store, with conspiring to launder tens of millions of Medicare dollars via Canada and Trinidad into Cuba’s national bank.

By late August, Sanchez, 47, had pleaded guilty and agreed to cooperate with authorities and repay the U.S. government $10 million, consisting primarily of residential investment properties he acquired with his wife in Southwest Florida.

The U.S. attorney’s office has said it has no evidence that the Cuban government was part of the laundering scheme, and Cuban officials have denied any involvement.

Sanchez, also a Cuban-born U.S. citizen, was indicted on the single conspiracy charge of playing a pivotal role in laundering the profits of 70 South Florida medical companies that falsely billed Medicare for $374.4 million and were paid $70.7 million.