One person with direct knowledge of her account at the time said that the woman — roughly two decades Mr. Cain’s junior and serving in a lower-level job — rebuffed him but that he continued to make advances. “She was uncomfortable, and it was inappropriate from the start,” this person said. “He was persistent.”…

Three people familiar with the details of the woman’s account said that she complained to higher-ups at the restaurant association. She then came to feel that there was a “change of attitude,” from her bosses toward her, they said, adding to her discomfort and leading her to finally decide it would be best to leave…

A handful of top supporters, contributors and friends of Mr. Cain’s were urging him on Thursday to stop talking about the sexual harassment allegations and to stop placing blame on his rivals, one adviser said.

But an aide said that Mr. Cain was angry about the allegations and was no longer heeding some of his advisers.