A woman who once worked for Jeffrey Epstein filed a complaint to the F.B.I. about his interest in “child pornography” in 1996, about a decade before investigators began scrutinizing his predatory behavior.

Brad Edwards, a lawyer who has represented many Epstein victims, said Friday night that if the F.B.I. had listened to Ms. Farmer, the government could have stopped Mr. Epstein in the 1990s and prevented hundreds of victims from being abused. He said the government until now has denied the existence of Ms. Farmer’s report, and that it was “shameful” that it was kept secret.

“There should be a full fledged investigation into every government employee who knew about this document and allowed a narrative to be publicized that it did not exist,” Mr. Edwards said.

An internal investigation of the Department of Justice’s handling of the Epstein case, released in 2020, made no mention of Ms. Farmer’s original complaint.