For the Los Angeles Police Department's pawn unit, last January's bust was routine. Saied Aframian, owner of a jewelry booth called The Bazaar, had scores of secondhand watches but no proof that he had purchased them legally.

One watch in particular stood out: a $2,700, 18-karat gold Corum with the words "Neiman-Marcus" inscribed on it. Police asked officials of the high-priced department store chain to run a computer check on the watch. They reported back that it had been stolen from their Washington store four months earlier.

Thus began the unraveling of what the FBI described yesterday as a multimillion-dollar, nationwide stolen property ring that was responsible for the largest robbery in the District's history: the September 1984 heist of more than $550,000 in jewelry from the Neiman-Marcus store in Mazza Gallerie, 5300 Wisconsin Ave. NW.

Two men were arrested in Los Angeles Thursday on charges contained in a D.C. Superior Court warrant of armed robbery in the daring daytime holdup at Neiman-Marcus, according to Carson Dunbar of the FBI's Washington field office.

Aframian, who authorities say was the ringleader and main fence for the operation, was convicted in Los Angeles earlier this year on seven counts of receiving stolen property, including two counts stemming from the Neiman-Marcus robbery.

Aframian and the two suspects arrested Thursday, Gregory Andre Hughes, 26, and Ralph Bryant, 22, both of the Los Angeles area, are allegedly part of a ring that FBI agents believe is responsible for stealing as much as $10 million in merchandise from jewelry and department stores across the country, Dunbar said.

After Aframian's arrest and arraignment in April, the FBI and local authorities began piecing together the case. In August, arrest warrants were issued for Hughes and Bryant. Authorities say that the two men were constantly on the move and were difficult to track down.

Along with the Neiman-Marcus holdup, the ring is suspected of having committed two other robberies in the Washington area this year in which hundreds of thousands of dollars' worth of merchandise was taken, Dunbar said. He declined to name the stores until employes are shown photos of the suspects.

The ring, which Dunbar said has stashed weapons around the country, is suspected in robberies in the Denver area and "up and down the West Coast," including one in August at the Beverly Wilshire Hotel in Los Angeles. Four men, including one who fired blasts from a submachine gun, burst into the hotel lobby, snatched $250,000 in jewels from a hotel store while startled guests dove for cover, and fled in a stolen white Cadillac.

"This is one of those cases where the agencies all worked together -- the Los Angeles Police Department, the Metropolitan Police Department [of Washington] and the FBI -- and used their resources," Dunbar said. "Twenty years ago, this case would have died."

The discovery of the stolen Neiman-Marcus watch in Los Angeles was the first tip-off that police were dealing with a nationwide ring, according to Dunbar. The FBI's investigation later revealed a number of robberies that matched the pattern of the Neiman-Marcus holdup.

Dunbar said that three weeks before the robbery, about four persons from the ring drove from Los Angeles to the District and rented rooms in a local "low-profile" hotel, where they paid their bill daily in cash.

While here, they canvassed a number of stores that were likely targets for a robbery, including Neiman-Marcus. They rented one car and purchased a secondhand car that they registered and licensed with temporary D.C. tags. They also purchased a variety of new clothes, Dunbar said.

The men stayed in frequent telephone contact with a member of the ring in Los Angeles, who provided them with cash for their expenses and instructed them on which stores to visit and what merchandise could be fenced in Los Angeles, according to special agent Daniel A. Reilly, an FBI investigator.

Detective Jim Wilke of the Los Angeles police, citing information provided by informers, said that members of the ring "have airline tickets provided for them and are told what stores to hit and what to get, and they were told they would be met anywhere at any time and be paid cash" for their booty.

Wilke said that the person who provided the instructions and bought the loot "goes to jewelry shows [in Los Angeles] frequently, and he knows which stores have the high-line merchandise and what moves" in the black market.

At about 1:30 p.m. on Sept. 25, 1984, two of the ring members, including one with a handgun, entered the Neiman-Marcus store and ordered clerks at jewelry counters on the first floor to place an assortment of rings and bracelets and about 70 watches into a shopping bag, specifying which items they wanted, Dunbar said.

The robbers then fled in their recently purchased car, which was driven by a third man. A short time later, they changed clothes and switched to the rental car. The men drove to Brentwood, Md., where they abandoned the rental car, finally fleeing the area in the car they originally drove from Los Angeles. Some of the members then drove to Los Angeles while others flew there from airports outside this area, according to authorities.

When the ring members returned to Los Angeles and turned over their loot, Dunbar said, they were paid about $90,000 for their part in the robbery, which he termed a "very high percentage" of the merchandise's value.

"Most robbers only get 5 to 10 percent of the value" of the goods, Dunbar said. "If they are connected with a good organization, they get a reasonable percentage . . . . It means that the fence has a good outlet and almost turns it over wholesale. That's how we identified this as a sophisticated organization."

Dunbar said that the investigation of the ring is continuing and that law enforcement authorities in the District will attempt to have the suspects extradited to stand trial here.