Ending a dramatic case involving drug trafficking, murder and corruption at the highest levels, a former Mexican deputy attorney general who faced 25 drug and money-laundering charges in the United States apparently committed suicide today in New Jersey, a Justice Department official said.

Mario Ruiz Massieu, a former top drug prosecutor once considered a national hero in Mexico, allegedly became entangled in the corruption and intrigue that characterized the presidency of President Carlos Salinas de Gortari in the early 1990s and ultimately was implicated in crimes including the assassination of his own brother.

Under federally supervised house arrest in New Jersey for the past several years, Ruiz Massieu stood accused of laundering $9.9 million through Houston banks while he was in office. A federal grand jury in Houston handed up the indictment against him in late August and Ruiz Massieu was to appear in court there on Friday for his arraignment.

Instead, Ruiz Massieu was found in his Palisades Park, N.J., residence, dead of an apparent overdose of unspecified antidepressants, said John Russell, a Justice Department spokesman. "We are confirming his death as a suicide," Russell said. Another law enforcement source said Ruiz Massieu died with his electronic monitoring anklet still on--a condition of his release on $500,000 bond.

His death ends one phase of a mammoth U.S. narcotics probe that had created law enforcement tensions between the United States and Mexico. Both countries wanted Ruiz Massieu: Mexico, for his alleged involvement in his brother's assassination as well as for narcotics trafficking, and the United States for the money-laundering case.

The U.S. case against Ruiz Massieu had centered on the years 1993 to 1995, during which he was accused of moving millions of dollars to Texas banks on a regular basis. U.S prosecutors alleged that the money came from "green light days" in Mexico--days on which traffickers were left alone to do their business in return for huge bribes, said a U.S. customs official.

Ruiz Massieu also was deeply entangled in the sensational case of the 1994 assassination of Jose Francisco Ruiz Massieu, his brother and the second-ranking official in Mexico's governing party.

As a top prosecutor, Ruiz Massieu had been placed in charge of the investigation into his brother's murder, but ultimately he stood accused of botching the probe and was suspected of being complicit in a cover-up surrounding the murder. Later, a Mexican judge convicted the president's brother, Raul Salinas, of ordering the murder.

Still under suspicion and facing charges in the case, Ruiz Massieu fled Mexico in 1995. En route to Spain, he was stopped at Newark International Airport and detained for attempting to travel with $40,000 of unreported cash. Later, as U.S. and Mexican authorities deliberated on how to handle the case, he was hit with immigration violations.

Ultimately released and placed under house arrest, Ruiz Massieu lived in New Jersey with his wife and daughter until his indictment on the money-laundering charges last month.

Ruiz Massieu's lawyer, Cathy Fleming of Manhattan, had reportedly complained that the federal case and the manner in which Massieu had been handled since he was first arrested in this country four years ago amounted to "harassment." She could not be reached for comment today.