A 16-year-old girl who was being held at the D.C. Jail on charges of soliciting prostitution has told police that she was sexually assaulted in her cell by a guard, D.C. police said yesterday.

The girl, a juvenile, told police when she was arrested that she was 19 years old, according to police. Her real age was not discovered until after police and correction officials investigated her charges that she was sexually assaulted at the jail.

Under D.C. law, persons under the age of 17 are not supposed to be housed at the D.C. Jail and are normally incarcerated in a receiving home.

D.C. police spokesman William White III confirmed yesterday that the D.C. police department sex squad is investigating the girl's charges that she was orally sodomized by a 27-year-old corrections officer about 5 p.m. Sunday. He said that the girl alleged the act was done in her cell and without her consent.

"The suspect is known and a warrant will be applied for by the D.C. police department's sex offense branch," White said.

Sources said that no one had been charged as of late yesterday afternoon.

LeRoy Anderson, spokesman for the D.C. Department of Corrections, confirmed that the department is investigating an incident in which a guard "allegedly had illicit sexual contact with an inmate." He said it would be "inappropriate" for him to release details of the investigation because it is "currently a potential personnel action" to determine whether the officer should be terminated from his job.

A spokesman for the American Federation of Government Employees, Local 1550, which represents correction department employes, declined to comment.

D.C. Corporation Counsel Inez Smith Reid said that when the girl was arrested for soliciting prostitution on April 30, she gave her birth date as Jan. 27, 1966, which would have made her 19.

Police sources said the girl appeared before a magistrate in D.C. Superior court the next day and was released. The terms of her release and the status of the case could not be learned because juvenile cases are confidential.

The girl was arrested for soliciting prostitution again on May 1, sources said, and again gave a fictitious birth date. On May 2, she appeared before the same magistrate in D.C. Superior Court, who, police sources said, was apparently annoyed that she was before him for the second day in a row for the same charge. They said he ordered that she be sent to the D.C. Jail.

On Sunday, according to police, the girl alleged that she was sexually assaulted by a corrections officer and an investigation revealed that she was 16. They said she was transferred to a receiving home in the District, where she is currently being held.

Police sources said that, although the girl said she was 19, they are uncertain if she provided any identification to prove her age. They said that on at least one occasion, she also gave them a fictitious name.

A prosecutor in the U.S. attorney's office, who spoke only on condition of not being named, said that it is not uncommon for juveniles who are arrested for prostitution to supply authorities with incorrect information.

The prosecutor said that the juveniles want to be identified as adults "because adults are brought into court the next day and released." Juveniles, on the other hand, "are taken into custody and placed into a receiving home," which prevents them from working on the streets.

"Most of these women carry fake IDs, and there's no way to check, like drug use," the prosecutor said. "More often than not we just don't find out until something else happens, like she gives it her age up or a friend gives it up."