Twenty-four years ago, Ms. Farmer was an artist who had entered the unorthodox life Mr. Epstein lived behind the doors of his luxury estates. Mr. Epstein had offered to help her painting career, but it all came to an abrupt end one night in the summer of 1996, when she says Mr. Epstein and his companion, Ghislaine Maxwell, began violently groping her.

She learned later that her 16-year-old sister, Annie Farmer, had been subjected to a troubling topless massage at Mr. Epstein’s ranch in New Mexico.

Ms. Farmer contacted the New York Police Department, and said she then went to the Federal Bureau of Investigation, offering to share what she knew about Mr. Epstein and the parade of young women being brought to Mr. Epstein’s houses. Though the bureau has never acknowledged such a contact, Ms. Farmer said the F.B.I. must have had a record of it, because agents came back to her — years later — with questions. She also went to leaders in the New York art world that Mr. Epstein and Ms. Maxwell frequented, and the sisters tried to tell their story to a national magazine.

In each case, their reports went nowhere.