"I do recall waking up in his bed naked," said Natalie, "and I am not somebody that goes home with somebody and has sex on the first date."
Rachel claims to have a vague but terrifying recollection of what happened during the night.
"I could feel someone on me," she said. "I knew he was trying to have intercourse with me, and then I said, 'Stop,' and I said, 'No.' And I couldn't move my body. ... I was panicking and I was so scared."
But all the women report the same thing -- that Marsalis was a complete gentleman in the morning.
"He was trying to be, you know, really nice and, like, caring and 'I am really into you,'" said Rachel.
Donna said she wondered what happened. "But I also was thinking, 'OK, I am just gonna take responsibility, and just move on,'" she said.
Though all the women say they felt something wrong and perhaps even criminal had happened in "Dr. Jeff's" apartment, they say he was able to convince them that everything was fine. And many of them told ABC they wanted to convince themselves of that.
None of them went to police. In fact, many of them willingly saw Dr. Jeff again.
"I thought, 'I don't want to be traumatized by this,'" said Rachel. "So I, I kinda tried to smooth things over or just go back to, like, the things I liked about him ... thinking, 'Oh, he's a doctor,' you know, like trying to rationalize this."
"We'd e-mail," said Natalie. "We'd talk on the phone every once in a while; maybe get together once every three, four months."
It would go on for years: Marsalis meeting women online, and then taking them out on dates.
"He would have never stopped, he would have continued to do what he was doing," said Lt. Thomas McDevitt of the Philadelphia Police Department's special victims unit.
McDevitt said police began investigating when one of Marsalis' ex-girlfriends reported being date-raped.
"She was a young professional woman," said McDevitt. "She was intelligent. She blamed herself in the beginning, that she didn't come forward [right away].
"We started an investigation thinking that, you know, he had somehow drugged her and sexually assaulted her."
Police searched Marsalis' apartment. And what they found, they said, shed a whole new light on the real identity of "Dr. Jeff" and his elaborate world of lies.
"Yeah, he never was a medical student," said McDevitt.
Visit the "Primetime" Web site Tuesday for Part II of the Jeffrey Marsalis story: What police discovered, frustrating obstacles for the prosecution and the culprit's final misstep. Later: Jeffrey Marsalis speaks.