4 Convicted of Laundering Drug Money : Trial: They were found guilty of funneling $350 million through businesses in Los Angeles’ jewelry district.

Four men were convicted in Los Angeles federal court Wednesday of laundering $350 million in drug money through jewelry companies doing business in the city’s downtown jewelry district.

A U.S. District Court jury convicted brothers Nazareth and Vahe Andonian and Argentine gold dealer Raul Silvio Rivas, the alleged mastermind of the scheme, of 25 counts of money laundering.

The Andonian brothers and Juan Carlos Seresi were also found guilty of conspiring to launder money, and Seresi was convicted on 20 money-laundering counts.

The same jury had convicted Rivas, 39, on Dec. 14 of conspiring to launder money. The jury is still deliberating money-laundering and conspiracy charges against a fifth defendant, Ruben Saini.

Assistant U.S. Atty. Jean Kawahara said the men convicted Wednesday face sentences of up to 20 years in prison on each of the money-laundering counts and five years on the conspiracy count.

Although the jury announced its verdicts Wednesday, Judge William Keller dismissed the panel before it could be polled. As a result, the verdicts will not be official until after a hearing today, defense attorneys said.

Earlier this month, the jury acquitted four defendants: Peniamin Mahseredjian, 37; Krikor Chahainian; Sepur Moroyan, 22, and Joyce Momdjian, 25. Charges against four others were dropped before the trial, and Keller dismissed charges against Vasken Anouchian, 25, of Glendale during the trial, citing insufficient evidence.

The case grew out of a 13-month federal investigation code-named “Operation Polar Cap” and has set the record as the longest criminal trial in Los Angeles’ federal courthouse, the U.S. attorney’s office said. Jury selection began last April 11 and testimony from nearly 100 witnesses began May 22.

Investigators estimated that between 1986 and February, 1989, when the defendants were arrested, the Andonian Bros. Manufacturing Co. and Ropex Corp., another downtown jewelry company involved in a separate trial, deposited more than $1 billion in cash into their accounts at Los Angeles-area banks.

U.S. Atty. Gen. Dick Thornburgh hailed the arrests, characterizing them as a major blow to international drug trafficking. Hundreds of personnel from half a dozen federal agencies and local police departments were involved in the investigation.

Authorities said the money laundering scheme, which also was operating in New York and Miami, was the largest and one of the most elaborate of its kind ever uncovered in the United States.

In several back rooms of Los Angeles’ downtown jewelry district, authorities said, the flow of drug money was so overwhelming that the cash--which the merchants falsely reported as legitimate jewelry profits--had to be counted on sophisticated high-speed machines.