Swiss authorities believe they have evidence showing the jailed brother of former Mexican President Carlos Salinas made tens of millions of dollars working for Colombian drug traffickers, The Wall Street Journal reported Friday.

Raul Salinas de Gortari is imprisoned in Mexico on charges of murder conspiracy and "inexplicable enrichment." The Swiss began investigating Salinas in 1995 after freezing $120 million in bank accounts he controlled.The Journal said the potential evidence against Salinas includes depositions given by U.S. drug agents and by Colombian and Mexican traffickers and financiers, some of whom are in U.S. jails or participating in the federal witness protection programs.

The witnesses apparently describe Colombian cartels making payments, scheduling flights and negotiating to recover drug shipments seized by Mexican officials, the Journal said. Their depositions are being reviewed by Salinas' lawyers, the paper said.

Sources familiar with the testimony told the Journal that a former accountant for the Cali, Colombia, drug cartel, testified that $80 million was paid by the cartel to Mexican politicians between 1990 and 1993, with about half that money going straight to Raul Salinas.

The Journal's sources said the testimony does not implicate Salinas' brother, but evidently some witnesses have testified that Colombian drug lords thought they were buying Raul Salinas' influence on the president.

Raul Salinas has said he accumulated his fortune legally but has admitted to capitalizing on "huge opportunities" available to him as a sibling of Mexico's president.

Carlos Salinas de Gortari's presidential term ended in 1994 amid his brother's scandals. He has said repeatedly that he was unfamiliar with his brother's financial dealings and has not been charged with any crime in Mexico.

If the Swiss can prove that the frozen money belonging to Raul Salinas is drug money, they will be entitled to keep it.

Salinas also is being investigated in the United States, Mexico, France and Britain, the Journal said.