Ghislaine Maxwell 'played a critical role helping Jeffrey Epstein abuse underage girls', it has been alleged.
The former girlfriend of the billionaire was arrested this morning at a 'gorgeous' mansion in New Hampshire, the FBI said.
Maxwell has kept a low profile since Epstein's suicide last year but the investigation into her involvement with Epstein has continued.
The longtime associate of Epstein - once also a friend of Prince Andrew - is accused of grooming girls as young as 14 for the financier as well as taking part in the sexual abuse herself.
The 58-year-old is due to appear over video link at a court in New Hampshire's Merrimack County.
The charges were revealed at a press conference this afternoon, where Audrey Strauss said her office would welcome the input of Prince Andrew.
The Acting United States Attorney for the Southern District of New York said: "We would welcome Prince Andrew coming in to speak to us and giving us an opportunity to hear his statement."
In a Grand Jury indictment unsealed this afternoon it is alleged that Maxwell "contributed to Jeffrey Epstein's abuse of minor girls by, among other things, helping Epstein to recruit, groom and ultimately abuse victims known to Maxwell and Epstein to be under the age of 16.
"The victims were as young as 14 years old when they were groomed and abused by Maxwell and Epstein".
The indictment also accuses Maxwell of lying "in relation to some of the minor victims" when under oath in 2016.
Maxwell has kept a low profile since the death of Epstein, a financier who was accused of raping and trafficking underage girls over nearly two decades.
Epstein, who pleaded not guilty, killed himself in his Manhattan jail cell in August last year.
Some of Epstein's alleged victims have said Maxwell lured them into his circle, where they were sexually abused by him and powerful friends.
Maxwell was an ex-girlfriend of Epstein who became a longtime member of his inner circle.
In a 2003 Vanity Fair article, Epstein was quoted as saying Maxwell was his "best friend.''
This afternoon Ms Strauss said: "Maxwell was among Eptein's closest associates and helped him exploit girls who were as young as 14-years-old.
"Maxwell played a critical role in helping Epstein befriend and groom minor victims for abuse.
"In some cases Maxwell participated in the abuse herself."
On the perjury counts, the Ms Strauss added: “Maxwell lied because the truth, as alleged, was almost unspeakable.”
She went on to urge anyone with information about the alleged crimes to get in touch with the FBI.
The indictment documents go on to allege that Maxwell "attempted to befriend" some of Epstein's "minor victims", asking them about their lives, schools and families.
She also took them to see films and to go shopping, it is alleged, and tried "to normalise sexual abuse for a minor victim, by, among other things, discussing sexual topics, undressing in front of victims".
The documents also claim she was "present for sex acts involving the minor victim and Epstein."
It continues: "In other instances, Maxwell encouraged minor victims to provide massages to Epstein, including sexualised massages during which a minor victim would be fully or partially nude."
Elsewhere it is alleged: "In some instances, Maxwell was present for and participated in the sexual abuse of minor victims.
"Some such incidents occurred in the context of massages, which developed into sexual encounters."
The search for Maxwell has been the subject of much speculation.
There were reported sightings and rumors of her whereabouts across the US and even abroad.
William Sweeney, special agent in charge of the FBI field office in New York, told the press conference that they had been "discreetly keeping tabs" on Maxwell's whereabouts and recently learned "she had slithered away to a gorgeous property in New Hampshire".
He added that she was "continuing to live a life of privilege while her victims live with the trauma inflicted upon them years ago.
"We alleged that from at least 1994 through at least 1997 Ms Maxwell assisted Jeffrey Epstein's abuse of minor girls by helping to recruit, entice, groom and abuse children under 18.
"She befriended the innocent, attempted to normalise sexual abuse, and worked to put victims at ease, aware the entire time of the abuse that would follow."
Maxwell’s father was the British media baron Robert Maxwell.
One of the alleged victims of Epstein, Virginia Giuffre, said in a civil lawsuit that Maxwell recruited her into Epstein’s circle.
She claims Epstein forced her to have sex with him and Prince Andrew, who has strongly denied the allegations.
After Maxwell said the allegations were untrue, Giuffre filed a defamation lawsuit against her in 2015.