NORRISTOWN, Pennsylvania—When Heidi Thomas first met Bill Cosby she was a 24-year-old starry-eyed aspiring actress who was thrilled to hear Bill Cosby wanted to mentor her.

Her agent said Cosby would call her at home in Littleton, Colorado, at a prearranged time one day in 1984. She waited nervously for the call.

“The phone rings and there’s Bill Cosby on the other end,” she said on Tuesday. “It’s… this voice you heard on TV and on the comedy stuff is on the other end of my phone. He was very kind and personable. He said he was looking forward to working with my agent. He was looking forward to giving back to the industry that had given him so much.”

Over the next two hours, Thomas told a jury how Cosby turned from mentor into predator.

She was the first of five other women expected to testify at the retrial for Cosby on charges that he allegedly drugged and sexually assaulted Andrea Constand in Pennsylvania in 2004. Cosby has denied all accusations of sexual assault from more than 60 women.

Thomas said after Cosby talked to her and her parents, they made arrangements for her to see him in Reno, Nevada, where he was performing at Harrah’s. Thomas said she thought she’d be staying in the hotel but when a driver picked her up at the airport on April 2, 1984, he drove her to a house far outside the outskirts of the city.

There, Thomas says, Cosby encouraged her to take a sip of wine so she could accurately portray someone who was intoxicated.

“I took a sip... and I can tell you it was a sip,” she said. “After that I don’t remember. I have little snapshots of the next four days after that.”

In one snapshot, Thomas said, she wakes up on a bed. She had her clothes on but Cosby was naked.

“He was forcing himself into my mouth,” she said. “And I remember thinking I felt sick and ‘How did I get here?’“

In the next one, Cosby was at the head of the bed and her head was at the foot of his bed.

“I heard his voice saying—and he always referred to himself in the third person or as ‘Mr. C’ or ‘your friend’—he said, ‘Your friend is going to cum again.’ And I’m thinking, ‘How did I get here? This isn’t what I’m here for.’”

Thomas said she went home after that weekend without ever confronting Cosby or telling anyone else what happened.

“ He always referred to himself in the third person or as ‘Mr. C’ or ‘your friend.’ ” — Heidi Thomas on Cosby

“I thought, ‘I must have said something that made him think this was acceptable,’“ she said. “I must have given him some signal. I knew for certain I wasn’t going to tell my agent because I was pretty sure what I’d done was my fault and I wasn’t going to tell my parents because they’d be so destroyed. So I was just going to move on and I did.”

A few months later Thomas said she decided to try to talk to him to find out what happened.

“I needed to fix this. I needed to find out what I said, what I did to mess that up,” she said. “He said he was going to be my mentor and I could call.”

Thomas said she called Cosby’s representatives who said she could talk to him when he was performing in St. Louis but she had to pay her own way there. Thomas said she went out to dinner with him and some friends but never got any time alone with him to ask him questions.

At the end of dinner, Thomas said she handed someone her camera and asked them to take a picture of she and Cosby.

“He wasn’t very happy with me and at that point it was pretty clear that whatever this mentorship thing was, it wasn’t happening,” she said. “I wasn’t going to get answers. I wasn’t going to learn what I did wrong so I really didn’t care if he was happy or not.”

That photo, as well as others that documented her trips to Reno and St. Louis, were submitted as part of the court record on Tuesday.

That dinner was the last time she had any contact with him, she said.

Thomas subsequently gave up her acting dreams and pursued teaching instead. She later married and at some point told her husband what happened to her, she said. She also talked about it with a psychologist who was trying to help her deal with her anxiety, she added.

Thomas will be back Wednesday morning so Cosby’s attorneys can finish cross-examining her.

Earlier in this day, Dr. Barbara Ziv, a forensic psychiatrist and sexual assault expert, testified for nearly three hours about typical behaviors and characteristics of sexual assault victims, about how sexual assault is the most underreported crime, and how delayed reporting is the norm for these offenses.

Ziv discussed how a victim’s memory can be impaired due to drugs or from the trauma of the sexual assault itself. She also said it’s fairly common in non-stranger rapes for victims to stay in touch with attackers afterward, especially if they work together.

“I think most women who are sexually assaulted by a non-family member but somebody that they know return to the previous relationship they had,” Ziv said. “So if it is an acquaintance they may call them or text them. Or if they call or text they’ll respond… at least for a period of time.

“It’s a very powerful drive to normalize a relationship; to make yourself feel safe both in your own judgment and the judgment of the individual and to psychologically ensure they’re not going to do further damage.”