A mentally retarded woman graphically described being raped to a Baltimore Circuit Court jury yesterday, but could not remember what her attacker looked like or identify him in the courtroom.

The woman, who has an IQ in the low 60s, told a jury she was forced to have sex with three men in a row in a Northwest Baltimore apartment in October last year. One of those men was her mentally retarded boyfriend, who was ordered to have sex by two other assailants, she said.

The case is complicated by DNA evidence that may not be reliable because of the multiple incidents. Defense lawyer Margaret A. Mead told the court that the 26-year-old woman is lying, and there is physical evidence to prove that her client, Dion Williams, 24, did not commit the rape.

According to court documents, Williams' DNA does not match the recovered samples. The woman's boyfriend's DNA was not tested. Police didn't identify a second suspect allegedly involved in the rape.

"I don't know why they are still holding Dion when DNA evidence is 99 percent sure," said Lynette Williams, the defendant's mother.

The woman is not being named because The Sun does not identify alleged victims of sexual assault.

The woman, who begins a job working at McDonald's Monday, described yesterday how she was terrified and assaulted.

"They wanted me to have sex with [my boyfriend], and I didn't want to, but I thought they would hurt me," she said. "I was scared to tell them no."

Police say the incident began Oct. 17 last year, when the woman and her 24-year-old boyfriend called an ambulance to take them to Mercy Medical Center because he was having a severe asthma attack. He was treated quickly and released.

As they walked outside and looked for a phone, two men approached them and told them they should be careful because they were in a dangerous area, the woman testified. The men told the couple to follow them to their apartment in the 4700 block of Greenspring Lane where they could use the phone, the woman testified.

However, when they arrived, they found no phone. It was then, the woman said, that she was raped.

The couple left the house and called police from a pay phone. Officers met them and took them back to the apartment. When they arrived, the woman pointed in the window and identified a man sleeping on the bed as one of her assailants. No one else was there.

Williams, who lives in the 400 block of North Glover St., was arrested and has been held on $300,000 bail. The arrest occurred hours after his release from jail, where he had been held on an unrelated charge.