It was the summer of 1996 when Maria Farmer went to law enforcement to complain about Jeffrey Epstein.

At the time, she said, she had been sexually assaulted by Mr. Epstein and his longtime partner, Ghislaine Maxwell. Ms. Farmer, then in her mid-20s, had also learned about a troubling encounter that her younger sister — then a teenager — had endured at Mr. Epstein’s ranch in New Mexico. And she described facing threats from Mr. Epstein.

Ms. Farmer said that when she discussed her concerns with the New York Police Department, then with the F.B.I., she also urged them to take a broader look at the people in Mr. Epstein’s orbit, including Donald J. Trump, then still two decades from being elected president. She repeated that message, she said, when the F.B.I. interviewed her again about Mr. Epstein in 2006.