On their second meeting, she said, he invited her to his suite at the Las Vegas Hilton, because he wanted her to practice improvising, even though she wasn’t an actor. He gave her alcohol to relax, she said, and soon afterward she felt woozy and sick, like she might topple.

Mr. Cosby beckoned her over, she said, pulled her down between his legs, so that her back was against his groin, and began stroking her hair. Ms. Lublin remembers wondering why he was doing that, and that she couldn’t understand a word he was saying. She has a few fractured memories of being guided by him down a hallway of the suite, and then nothing, until she woke up at home in her bed.

Ms. Lublin was mortified, but not, at the time, because of anything Mr. Cosby might have done. “I looked at it as ‘Oh my god, Lisa, you got sick from alcohol; you don’t even remember how you got home,’” she said.

When Mr. Cosby reached out to her again, and even forged a friendship with her mother, she felt reassured: Maybe her blackout behavior hadn’t been that bad. Ms. Lublin said she and Mr. Cosby met several times after that — though never alone — and that at his urging, she began running at a track as he looked on.

When bystanders asked what Mr. Cosby was doing there, Ms. Lublin said he replied, “I’m out here with my daughter, Lisa.” (Lisa is the name she goes by.) Eventually they fell out of touch.

After Ms. Dickinson went public with her story late in 2014, Ms. Lublin began reconsidering what really happened at the hotel that night.