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.

Ms. Farmer said she has long wondered how law enforcement agencies handled her complaints in 1996 and 2006.

And she said she has been wondering in particular whether federal authorities did anything with her concerns about Mr. Trump. She said that she raised his name both times, not only because he seemed so close to Mr. Epstein but because of an encounter, which she has previously described publicly, that she said she had with Mr. Trump in Mr. Epstein’s New York office.

The encounter with Mr. Trump, Ms. Farmer said, occurred in 1995 as she was preparing to work for Mr. Epstein. She said she told the authorities that late one night, Mr. Epstein unexpectedly called her to his offices in a luxury building in Manhattan, and she arrived in running shorts.

Mr. Trump then arrived, wearing a business suit, and started to hover over her, she said she told the authorities. Ms. Farmer said she recalled feeling scared as Mr. Trump stared at her bare legs. Then Mr. Epstein entered the room, and she recalled him saying to Mr. Trump: “No, no. She’s not here for you.”

The two men left the room, and Ms. Farmer said she could hear Mr. Trump commenting that he thought Ms. Farmer was 16 years old.