Former lead prosector in the Robert Mueller Russia probe Andrew Weissmann is rejoining Jenner & Block after almost a decade in public service.

Weissmann was previously a partner at Jenner & Block between 2006 and 2011, and will return to the firm on 1 July to co-chair its investigations, compliance and defence practice.

As well as recently serving on Robert Mueller’s Special Counsel investigation into Russian interference in the 2016 US election, Weissmann was chief of the Fraud Section of the US Department of Justice Criminal Division between 2013 and 2017, and general counsel of the FBI between 2011 and 2013.

Katya Jestin, co-managing partner at Jenner & Block, said: “I am thrilled to welcome back my friend and colleague. I know of no more skilled trial lawyer or tenacious investigator. His creative thinking and unparalleled experience in corporate compliance and in FCPA [Foreign Corrupt Practice Act] investigations will prove invaluable to our clients.”

During his time heading the Fraud Section at the DOJ, Weissmann helped oversee some of the biggest white collar crime cases of recent years, including the Libor, Forex, Oderbrecht and Volskwagen investigations.

Randy Mehrberg, co-managing partner with Jestin, said: “Andrew did ground-breaking work in the field of corporate compliance, both here and while leading the fraud section. His experience will help our clients mitigate the risks associated with government investigations. Andrew is also a top-flight trial lawyer, who notched many civil litigation victories during his prior tenure at Jenner & Block. Our corporate clients are delighted that he is returning to private practice.”

Before his previous spell at Jenner & Block, Weissmann spent time as the director of the Enron Task Force and as the chief of the Criminal Division for the Eastern District of New York, where he helped prosecute members of the Colombo, Gambino and Genovese crime families.

Weissmann said: “When I first joined Jenner & Block, I was drawn to the firm’s combination of dedication to excellence, commitment to pro bono service by every firm lawyer, and the teamwork and collegiality demanded of its lawyers—from first-year associates to senior partners. I could not ask for a better environment in which to practice law.”

The high-profile hire for Jenner & Block comes in the same month that former chairman Craig Martin left the firm along with five other partners to open a Chicago office for Willkie Farr & Gallagher.