MEXICO CITY -- Despite Cuba's denials, the late Mexican drug baron Amado Carrillo Fuentes is believed to have laundered millions in drug money through a Havana-registered trading firm, officials familiar with the investigation say.

Mexican law enforcement officials are looking into the activities of a Colombian trading firm known as Peter Lever in Havana, according to one official and confidential documents seen by The Herald. Investigators believe the firm was registered in Havana through Carrillo Fuentes' front men, and carried out financial transactions from Colombia, Nicaragua and Switzerland.

``We believe he registered that company in Cuba through his straw men, and used it to launder drug money,'' a well-placed official from one of the countries familiar with the investigation said. ``We are looking into it.''

Cuba does not reveal its registries of foreign companies, to protect them from possible U.S. reprisals under the U.S. trade embargo on the island. In Colombia, Peter Lever is not registered as a corporation in the Bogota or Cali Chambers of Commerce, but could be registered somewhere else, officials say.

Asked about the case, Mariano Herran Salvatti, Mexico's top anti-drug official, said he could not comment. He would say only that ``We are awaiting more data from Cuban authorities'' on Carrillo Fuentes' activities on the island.

A spokesman for Colombia's police chief, Gen. Rosso Jose Serrano, said his boss ``does not remember'' receiving any request from Mexican officials to look into Peter Lever in Colombia. Serrano aides said they are not familiar with the company.

Six-month tug of war

The Mexican investigation into the alleged Colombian drug money-laundering firm is the latest chapter in a six-month tug of war between Mexican law enforcement agents and the Cuban government.

At first, Cuba ridiculed reports that Carrillo Fuentes had even spent time on the island.

At Mexico's insistence, and following press reports that Carrillo Fuentes' associate, Jesus Bitar Tafich, had told Mexican authorities that the drug lord had a wife and daughter on the island, Cuba acknowledged in a Sept. 22 letter to Mexican authorities that Carrillo Fuentes had visited the island on at least four occasions between 1993 and 1997.

But the Cuban government letter, which made its way to the Mexican press, claimed that Carrillo Fuentes did not engage in any commercial activities on the island. It asserted that the drug lord had made inquiries about possible investments in Cuba's Mariel free trade zone, but that no business deals had materialized.

Letter called `snow job'

A senior Mexican official told The Herald at the time that ``the [Cuban government] letter is a snow job.''

Among other things, the Cuban letter seemed to contradict Bitar Tafich's statements that Carrillo Fuentes had lived in a Cuban government guest house in Havana's Vedado section, and that he received preferential treatment on the island. Cuban authorities denied both claims.

Carrillo Fuentes was described by U.S. officials as the world's biggest drug trafficker before his accidental July 4 death during cosmetic surgery in Mexico City. He visited Cuba, Chile and Argentina frequently under the name of Juan Antonio Arriaga Rangel, Mexican officials say.

Despite investigators' possible new findings on Carrillo Fuentes' business activities in Cuba, some Mexican officials say Mexico is unlikely to pursue the case aggressively, given the close relations between the two governments.