Three men, all in their mid-21s and all with histories of criminal convictions, were ordered held without bond by a D.C. Superior Court judge yesterday, for allegedly killing a Washington merchant who was shot Friday while under surveillance by dozens of uniformed officers.

Superior Court Judge George Bevercomb, citing the "seriousness of the crime," ruled that the men will be held under five-day preventive detention with preliminary bearings scheduled for Thursday.

The three men, who all wore shorts and knee-high white socks in court yesterday, were identified as Melvin Gary Stewart, 23, of 1131 7th St. NE. and Arthur Swarn of 6305 Kilmer St., Cheverly.

Meanwhile police continued to investigate the shooting death of Leon Grant, 30, and said other arrests in the case are possible.

Grant was shot once through the right side of his throat Friday afternoon, according to police, by one of three men who rushed him as he sat in his Jeep with $2,400 in cash had just withdrawn from the Park Road branch of the Riggs National Bank to pay employes at his woodworking firm, Grant & Green.

Police had staked out Grant and the street around the bank because Grant had reported to them two weeks earlier that he knew an attempt would be made to rob him as he made his routine Friday trip from the bank to his office with the money, police said.

As Grant entered his Jeep with the cash Friday afternoon, when three men ran towards him and one of the men fired one fatal shot that tore through his throat. Police had dressed Grant in a bullet proof, nylon and fiber glass vest to protect him, in the event of gunfire.

Police then arrested the three men who were arraigned for murder in court yesterday.

The arrests did not end the investigates, however, police reported. Although detectives would not say how Grant knew an attempt would be made to rob him, they did say that someone who knew Grant's Friday routine informed the men who attempted to rob him of how and when Grant traveled to the bank to get cash for his payroll. Police said Grant knew one of the men charged with his murder, but would not say which of the three it was.

According to police, one of Grant's former employers is being questioned in connection with the case to determine if she might have informed the subjects about Grant's pay-day routine. Police said the woman will be charged with complicity in the murder if it is determined that she told the suspects about Grant's routine with the intention of sharing the stolen money.

At a press conference at D.C. police headquarters yesterday, Joe Gentile, a police spokesman refused to discuss the police stakeout procedure that failed to prevent Grant's murder. But Gentile said the police department will conduct "an intense investigation and close review of those procedure."

"Mr Grant believed in law and order," said Gentile by way of explaining why Grant, a civilian, was allowed to take part in the police operation "He wanted to help us apprehend these men as they committed the crime . . . It is because of people like him that crime is down in this city. People know they have to take part in helping the police to fight crime."