Police who arrested an 11-year-old Northwest boy after he struck a friend with a baseball bat "acted according to department procedures," according to Deputy Chief James P. Shugart, commander of the 4th District, who said he has concluded a preliminary investigation of police handling of the case.

Shugart said the arrest was proper under the circumstances, but he declined to outline what factors officers considered in taking custody of the boy -- who later was sexually assaulted in a cell at Superior Court -- saying the case involves a juvenile and is therefore confidential.

"I can't say what the mitigating circumstances were," Shugart said. "Another person was seriously injured . . . . At this stage, I find that the policies of the department were followed."

Community leaders and juvenile justice specialists continued yesterday to question the appropriateness of the arrest. A source familiar with the incident said that social workers at the courthouse, who thought the charge should not have been brought against the child, took extraordinary measures to have him released.

Social workers "went beyond their normal routine," said this source, who declined to elaborate.

The boy -- who had no previous trouble with the law and had a history of psychiatric treatment for depression -- said he was just horsing around with a friend last May when he "accidentally" hit the friend on the head with a baseball bat.

The other boy suffered a deep cut and his mother complained to police at the 4th District. Officers in the Youth Services Branch charged the 11-year-old with felony assault with a dangerous weapon and turned him over to deputy U.S. marshals at court.

Once in the cell, the boy was attacked by a 14-year-old and a 17-year-old with several prior convictions. The boy was forced to commit sodomy and later was found to have contracted syphilis.

"It's certainly unfortunate that this would happen to a youngster in the cell block," Shugart said. "But we don't have responsibility for what happens in the cell block."

Officials in the Marshals Service have declined to comment, except to say that they have investigated the incident and will send a report to the Justice Department.