The lawyer for a 27-year-old social worker with the public defender's office on trial in the sexual assault of a 15-year-old boy she was visiting at a juvenile detention center says that she is the real victim in the case, and that the troubled teen raped her in a locked meeting room.

Amy Bibighaus is charged with third-degree sexual assault - the felony charge prosecutors can bring against someone age 21 or older for having sex with a 14-year-old or 15-year-old. She could receive a maximum sentence of 10 years in prison.

The issue of rape has been part of Bibighaus' defense throughout, and her lawyer, Domenic R. Lamele, raised the issue yesterday in cross-examination of the teen-ager in Baltimore County Circuit Court.

Alleged victim and defendant made an odd pair yesterday in court. Bibighaus watched witnesses intently from the defense table and jotted down notes. She did not testify.

The baby-faced youth, who is still institutionalized, mumbled answers to Lamele's cross-examination, speaking in monotone about a history of behavioral problems, including assaults.

The teen-ager was sent to the Charles H. Hickey Jr. School after committing an armed robbery, according to testimony yesterday. The Sun does not identify juveniles or alleged victims of sexual assaults.

The case against Bibighaus stems from a visit Feb. 12 that she and a lawyer from the public defenders office paid the 15- year-old, who was then housed in a seclusion unit at the Hickey School in Cub Hill.

Public defender Carriellen Beaudreau said she had asked Bibighaus to accompany her because she knew the conversation with her client was going to be sensitive, and she wanted a witness. Bibighaus, whom Beaudreau described as a respected social worker in the office, had worked with the teen.

Beaudreau said she could not talk about the content of the conversation because of attorney-client rules.

But Lamele, while cross-examining witnesses yesterday, suggested that Beaudreau was going to tell the teen that she could no longer represent him.

The two women met with the youth in an administrative office, Beaudreau and Hickey School staff members said. After the three spoke, witnesses said, the teen asked to speak to Bibighaus alone.

Beaudreau left the room.

The teen testified that he propositioned Bibighaus, that they pulled down the shades of the office and locked the door. Another staff worker testified that she saw the teen and Bibighaus peek through the blinds.

"I ain't never pushed her," the teen testified. "She ain't never reached for the door."

The staff worker testified that she came over to the office window and saw Bibighaus and the teen in a consensual sexual position. She said she tried to open the door but it was locked.

Lamele challenged that version, almost yelling at the teen to say why he told police that night he hadn't had sex with the social worker. Lamele said the lock had malfunctioned, making it impossible for his client to leave the room.

"You thought you were going to be charged with rape, didn't you?" he shouted at the teen.

"No, when I was in the room I told Amy I wasn't going to say nothing," the teen responded.

The staff worker said she called her supervisor, and William Young, an intake case manager, said he unlocked the door.

Young said the youth was sitting behind the desk, grinning. Bibighaus was sitting on the couch.

"She said she had two other clients to see," Young said. "Nothing was out of place in the room. She seemed normal."

Bibighaus' trial is to continue next week.