The mother of a 10-year-old Southeast Washington girl whose fifth-grade teacher has been charged with sexually assaulting her in a locked classroom last month alleged yesterday that the school's principal refused to notify police about the incident because she didn't believe the girl's story.

The mother's allegation followed a preliminary hearing in D.C. Superior Court in which a police detective testified that authorities were not notified of the alleged assault until two days after the principal learned of it, and that it was Children's Hospital that brought the girl's complaint to police.

The police account was disputed, however, by Shelton Lee, director of security for the schools, who told a reporter that his office notified officials in the sex branch the day the alleged incident was reported.

Lee said school administrators are not required to go to police when such complaints are lodged but that it is standard procedure to notify the security department.

The teacher, Roy Lee Alston, 43, has been charged with taking indecent liberties with a minor child in the alleged incident at Moten Elementary School in Anacostia.

Alston was arrested on a warrant Feb. 15, and appeared yesterday at the preliminary hearing, where Judge Reggie B. Walton ruled that there was probable cause to send the case to a grand jury.

At the hearing, Detective Steve Matthews of the police department's sex offense branch testified that authorities were not notified of the complaint until Jan. 28, two days after the girl had given what police described as a tearful account of the alleged incident to Moten Principal Valerie S. Green.

On Monday, the girl's mother filed a $7.5 million damage suit against Alston, Green and the city, contending that officials at Moten knew of a similar previous incident allegedly involving Alston and did nothing to prevent a recurrence.

Law enforcement sources said they have not verified that any such previous incident occurred and added that no charges had been filed. Alston's attorney, John Perazich, said he was aware of allegations of a previous incident but declined further comment. Perazich also declined to comment on the present charge.

The mother maintains in the suit that her daughter's "safety and well being were intentionally jeopardized" by school officials and that she has suffered "physical injuries as well as severe and permanent mental injuries" because of the alleged assault.

According to a police affidavit filed in the criminal case, the girl alleged to Green that Alston unbuttoned her blouse and fondled her after detaining her inside the classroom while other students were at lunch.

The girl's mother said in an interview yesterday that she and her husband met with Green the following day. According to the mother's account, Green said she didn't believe the girl's story and argued against calling the police, saying "the sex squad can't do anything." A schools spokeswoman said Green has been advised by counsel not to comment on the matter.

The girl's father said he took his daughter the following day to Children's Hospital, where she was examined by a child psychiatrist. The psychiatrist notified police, he said. The father said he then took the girl to police headquarters, where she was interviewed by detectives. A warrant was issued for Alston two weeks later.

Alston, who is on leave from the school system, could be sentenced to a maximum 10 years in jail if convicted on the charge.

Last September, Moten was the focus of widespread parental concern when a student reported that she had been raped there. At least 200 parents volunteered to patrol the school's hallways. Later, the report proved to be false.

Nevertheless, as a result of the concern, Green responded to the report by instituting new security measures, including a requirement that students never be alone in hallways and washrooms.