A sexual assault on an 11-year-old Northwest boy in a cell at D.C. Superior Court last May occurred at a time when deputy U.S. marshals were making repeated complaints that they did not have enough personnel to monitor the cells and that they and the prisoners might be in danger of attack.

"We predicted that something like this was going to happen," said Wallace Roney, president of the local union of the American Federation of Government Employees that represents the deputies.

"We have filed numerous complaints about shortages of manpower. At the time the incident occurred, we had filed those complaints," Roney said.

Deputy marshals have reported that at various times there have been as few as seven deputies in the Superior Court cell block to supervise as many as 250 prisoners.

Roney and other deputies said that the staffing level is too low to pay adequate attention to the prisoners in each cell.

Roney said he had no direct knowledge of what occurred in this case, in which the boy was twice attacked by 14-year-old and 17-year-old cell mates, who forced him to commit sodomy.

The boy, who is now 12, was later found to have contracted syphilis.

A spokesman for the Marshals Service said last night that officials would not comment on staffing complaints made by the deputies because the family of the boy has said that it plans to sue the service for failing to protect him.

Officials of the service said earlier that they have conducted an investigation of the incident and will send a report to the Justice Department.

Roney said that deputies normally would not place an 11-year-old in a cell with older youths, but would put him in a cell by himself or seat him outside a cell near a deputy who could watch him more closely.

"They deputies usually put him in an empty cell. They won't put him in with older guys," Roney said. "But when you're understaffed, the poor deputy has probably got four or five other things to do. If that the attack happened, it's because the poor guy was probably working his buns off."

Deputies have been joined in the past in their complaints about staff shortages by judges in Superior Court and in U.S. District Court.

In 1979, the health and safety administrator for the Marshals Service, Clinton C. Mitchell, declared working conditions in the federal courthouse cell block unsafe because of low staffing.

In May 1980, then-Marshal J. Jerome Bullock wrote his superiors saying the "manpower situation is at a critical level . . . . " In October 1980, Superior Court Chief Judge H. Carl Moultrie I wrote Attorney General Benjamin R. Civiletti complaining that the Marshals Service was not carrying out its duties.

In August 1983, the chief shop steward for deputies in Superior Court, Hordon H. Evono, wrote then-Marshal Robert L. Matthews complaining that the cellblock there was "continually understaffed" with 10 deputies to 200 prisoners, but that as few as seven deputies had been asked to supervise 250 detainees.

Roney said these complaints have gotten virtually no response from superiors at the Marshals Service and Justice. Officials hired 10 correctional officers earlier this year to help monitor cells in Superior Court, he said, but he insisted that at least 50 additional deputies should be hired to adequately staff the two courthouses.

He said he fears that officials will blame deputies for the attack on the 11-year-old, when, he said, the blame should be placed on management staffing.

"The union concern is that they're going to hurt one of the deputies down there by saying he wasn't doing his job," Roney said. "Our position is that we do our job and overdo our job. Each deputy should get a medal."