Audrey Strauss, the prosecutor who decided to arrest Ghislaine Maxwell, acted with lightning speed just days after her predecessor was unceremoniously fired by Donald Trump.
Geoffrey Berman, the outgoing US attorney for the Southern District of New York, had presided over a long inquiry which had seen him make a series of high profile public statements about the Duke of York, including that the duke was offering "zero co-operation".
On June 20, Mr Trump ejected Mr Berman and Ms Strauss, 72, his deputy, took over his cases.
Her decision to move quickly in the Jeffrey Epstein case drew plaudits from women who have accused the late financier, and questions over why the arrest of Ghislaine Maxwell had not happened sooner.
Maria Farmer, who made the first criminal complaint against Epstein in 1996, wrote on Twitter: "Strauss is doing what Berman wouldn't, his job!" When asked about the timing of the arrest, Ms Strauss said: "That was when we were able and prepared to move to arrest her."
Ms Strauss took charge because Mr Trump's nominee to replace Mr Berman has to be confirmed by Congress.
The nominee is Jay Clayton, chairman of Securities and Exchange Commission, but he faces opposition from Democrats.
According to colleagues Ms Strauss has always been keen to stay out of the spotlight, but has a deep knowledge and experience of her department. She first served as an assistant US attorney in New York's Southern District from 1976 to 1983, prosecuting more than 20 cases, before moving into private practice.
She returned as Mr Berman's deputy and has bee involved in the financial case brought against Michael Cohen, Mr Trump's former personal lawyer, and an investigation into the business dealings of his current personal lawyer Rudy Giuliani. Mr Giuliani has denied any wrongdoing.
A former colleague of Ms Strauss said: "I would expect that she was very much involved in all of the important cases in the office." Another said she would "doggedly pursue" investigations and was "uniformly viewed as doing the right things for the right reasons."
One former colleague called her a "titan" with a "fantastic reputation". Paul Shechtman, a former federal prosecutor in New York who has worked with her, told the Washington Post: "She grew up in that office. The traditions of that office are embedded in her."
Ms Strauss, a mother of four, is originally from Philadelphia, the daughter of Russian immigrants, and her brother worked for Nasa.
She is a Democrat who has donated to Barack Obama, Joe Biden and Hillary Clinton.
When he left his cases with her Mr Berman said he could do so "in no better hands than Audrey’s."
He said: "She is the smartest, most principled, and effective lawyer with whom I have ever had the privilege of working."