The 13-year-old's dark blond hair frames her face in a Dutch-boy haircut. Her face fills with a smile when she talks about computer games, soccer and puzzles. She rolls her eyes while she's thinking out her answer to a question.

"She's a loving, mellow kid," says Donna Anderson, the child's former schoolteacher and now her foster mother. The child, a student at Hillside Intermediate School, is mentally handicapped.Anderson believes her foster daughter was raped by an older, non-handicapped student during lunch hour on Sept. 19 at the Salt Lake junior high school. Based on physical evidence and a Salt Lake Police investigation, a 15-year-old youth is being held at the Juvenile Detention Center. The youth was charged with rape of a child under the age of 14, a first-degree felony, according to Roy Whitehouse, juvenile trial court executive.

Anderson contends school officials, despite the evidence discovered by the police investigation, aren't listening to her foster daughter because the girl has difficulty communicating verbally.

Nancy Hardy, pupil services director for the Salt Lake School District, downplays the incident. "First of all, let me say there was probably not anything that occurred at Hillside. There was certainly not a rape, as far as our investigation goes.

"I've been in the school system in a junior high setting for 23 years. This is the first time anything has been alleged like this."

But while what happened in the school that day remains disputed, Anderson believes the incident underscores a crucial issue: the vulnerability of the handicapped population. "I think they are chosen prey."

Her foster daughter, like many others with special needs, will be victimized her entire life because of her trusting nature, Anderson said. "The prognosis is she'll be abused and abused and abused."

Social services experts agree the extent of the problem is difficult to determine. No Utah agency tallies reports of abuse separately for handicapped people. Relatively few incidents are reported. When they are, sometimes it's easier not to believe a handicapped victim. And even when there is evidence to prove an assault occurred, such cases can be difficult to push through the legal system.

A national advocacy organization for the developmentally disabled, Easter Seals Foundation, said that up to 90 percent of disabled people will suffer some type of sexual assault in their lifetimes. "What makes people with disabilities very susceptible is they are forced to be dependent on other people," according to Patricia Giggans, executive director of the Los Angeles Commission on Assaults Against Women. "They're forced to be more trusting. Their survival depends on them being taken care of."

"I think it's imperative to understand that the handicapped population is incredibly vulnerable," says Christine Waters, director of the Salt Lake Rape Crisis Center. "The problem is many people don't think the handicapped are credible victims."

According to statistics, about 4 percent of the rape center's clients are handicapped. But the director thinks that figure understates the problem, as many incidents are not reported - or worse, not believed. No matter who is raped or sexually assaulted, it is considered a criminal act, Waters said.

Sexual abuse of handicapped people is "possibly more prevalent than you think," said Debra Mair, director of the Independent Living Center.

Officials say getting convictions in child-sexual-abuse cases is difficult with any victim who is not articulate - and hence, according to the legal system, not as credible.

"It's not just with people who have mental retardation," said Terry Twitchell, public information officer for the Department of Human Services. "Little kids come in and say something happened and the reaction is `they're making it up,' because they don't verbalize well. If you can't verbalize, you can't be a victim, I guess."

While many advocates argue for children's legal rights in sex-abuse cases, few voices shout for the cause of mentally retarded victims. Some handicapped people might not know how to defend themselves from an attacker. Others might not have the verbal skills to describe an assault or identify the assailant. In addition, when handicapped students are placed in regular classrooms - or as adults, placed into everyday society - others might take advantage of their vulnerability.

Prosecutors may be more reluctant to argue cases where the victim is mentally retarded.

Rob Denton of the Legal Center for the Handicapped said he has no reason to believe that people with physical or mental disabilities are the victims of assault more often than others. "My feeling is there may be a reluctance to prosecute because the witness is not necessarily going to be quite credible," he said. "That's particularly true for the mentally impaired. Sometimes I think they're considered fair game."

Anderson insists that the district provide a safe environment for her foster daughter before she'll allow her to return to school. She is providing counseling to help the child through what she believes is a traumatic situation.

Anderson said she was informed 30 hours after the incident occurred. "There was probably some exploring going on," is what Anderson said she was told in the call from Hillside Principal Scott Bowles. "Both students were found with their pants down. I don't think there was penetration. At this point, it's your decision whether you want to go to the police," Anderson says Bowles told her.

Bowles has not responded to repeated efforts to contact him for comment.

Anderson's foster daughter and the the boy accused of attacking her were interrogated together for hours in the principal's office. Non-handicapped rape victims aren't treated that way, she said.

Hardy, the district official, said the school did not turn its back on the child but said she wasn't telling a credible story. The student reported the incident by saying a boy had "bothered" her. "The word rape was never used," Hardy said. "Intercourse was a word that was never used.

"She never said that her clothes were stripped off. She never said that she was forced on the floor." The gym where the girl said the incident happened reportedly was locked at the time, and the teacher who was patrolling that hallway said it wasn't left unattended for more than a minute.

"You have to understand the mental function of the child," Hardy said. "The child is intellectually handicapped to the degree that she functions as a small child.

"This child is one who is always asking for help at the school. They help her put food on the lunch tray. They help her open her locker."