Here's how the FBI tracked Ghislaine Maxwell to her $1 million New Hampshire mansion using her cell phone data

• An unsealed FBI warrant application spotted by the Daily Beast has revealed how the security service was able to track Ghislaine Maxwell to her $1 million mansion in New Hampshire.
• The FBI was able to use a portable spying device known as a "Stingray," which functions like a dummy cell phone tower.
• The agency had already tracked down Maxwell's phone, which she had registered under the name "G Max."
• Maxwell is awaiting trial on charges of procuring girls for Jeffrey Epstein, the American financier and convicted sex offender who died in his jail cell in 2019, and of perjury. Maxwell has pleaded not guilty.

An unsealed court document has revealed how the FBI finally managed to pin down the whereabouts of Ghislaine Maxwell, the British socialite awaiting trial on charges related to Jeffrey Epstein's child sex trafficking ring.

The document, which was first reported on by the Daily Beast, is an affidavit that was filed by an FBI agent on July 1, 2020 - the day before Maxwell was arrested at her $1 million New Hampshire mansion.

The affidavit is an application for a search warrant asking to use an "investigative device or devices" that would be capable of receiving signals from nearby cellphones.

It notes that the FBI had already obtained a warrant to track Maxwell's GPS signal to a certain radius, as it had identified a cell phone account registered to her under the name "G Max," but wanted to home in on exactly which building she was in.

The affidavit describes the requested device, saying it "may function in some respects like a cellular tower, except that it will not be connected to the cellular network and cannot be used by a cell phone to communicate with others."

As the Daily Beast notes, this strongly suggests the FBI used an espionage device known as a "Stingray."

Stingrays are small enough to fit inside a briefcase, and act as a kind of dummy cell phone tower. Nearby cell phones send signals to the Stingray rather than real cell phone masts in the vicinity, and the Stingray records their location and the registered user's ID.

Read more: The untold story of Ghislaine Maxwell's secret husband, Scott Borgerson

Prosecutors previously said FBI agents found a cell phone wrapped in tin foil in Maxwell's home, which they described as a "seemingly misguided effort to evade detection [...] by law enforcement."

Maxwell is currently awaiting trial on charges of procuring girls for Epstein between 1994 and 1997, and of perjury. She has pleaded not guilty. She was denied bail for a second time in December.