WASHINGTON (AP) — Attorney General William Barr on Thursday named Timothy Shea, one of his closest advisers, to be the next top prosecutor in the nation’s capital.

Shea will lead the largest U.S. attorney’s office in the country, which has been historically responsible for some of the most significant and politically sensitive cases the Justice Department brings in the U.S.

He is a senior counselor to the attorney general and was Barr’s right-hand man helping institute reforms at the federal Bureau of Prisons after Jeffrey Epstein’s death at the Metropolitan Correctional Center in New York City.

As the U.S. attorney in the District of Columbia, Shea would oversee some of the lingering cases from special counsel Robert Mueller’s Russia investigation, along with a number of politically charged investigations. The office is also generally responsible for handling potential prosecutions if Congress finds a witness in contempt.

“Tim brings to this role extensive knowledge and expertise in law enforcement matters as well as an unwavering dedication to public service, reflected in his long and distinguished career in state and federal government,” Barr said in a statement. “His reputation as a fair prosecutor, skillful litigator, and excellent manager is second-to-none, and his commitment to fighting violent crime and the drug epidemic will greatly benefit the city of Washington.”

Prosecutors from the U.S. attorney’s office had been investigating former FBI Deputy Director Andrew McCabe, a frequent target of President Donald Trump’s wrath, and the prospect of charges seemed likely in the fall after his lawyers failed to persuade senior Justice Department officials that he didn’t intentionally lie to internal investigators. Little has been said about the case in recent months.

The position generally requires Senate confirmation, but the law also allows federal judges to vote to appoint a U.S. attorney after a 120-day window. That was the case with Geoffrey Berman, the U.S. attorney in Manhattan.

Shea, a Boston-area native who comes from a family of first responders, is widely seen as being able to bridge a gap between law enforcement officials and the community, especially in Washington. The office is unique because its 300 or so prosecutors have jurisdiction to prosecute both local and federal crimes in the nation’s capital.

“He’s the definitive public servant,” said Jim Pasco, the executive director of the National Fraternal Order of Police. “He has a real reverence for the law and a real dedication to making communities safer.”

Shea has served in a variety of roles in the Justice Department from working as a line prosecutor to being associate deputy attorney general. As an assistant U.S. attorney, he prosecuted violent crimes, fraud, public corruption and drug trafficking cases and he’s also led a task force that was responsible for investigating and prosecuting prison crimes and had also worked as a congressional staffer in the House and Senate.

He was the chief counsel and staff director for the U.S. Senate Permanent Subcommittee on Investigations, which was chaired at the time by Sen. Susan Collins, a Maine Republican, and also worked on the staff of the House Appropriations Committee.

Collins said in a statement that Shea “did an outstanding job leading in-depth investigations into issues ranging from consumer protection to government waste, fraud, and abuse.”

“With his decades of legal experience in both the private and public sectors, Tim has a wealth of knowledge that will serve him well in his new role,” she added.

In the wake of Epstein’s death, Barr and Shea worked hand-in-hand to manage the crisis and investigation into the circumstances surrounding the wealthy financier’s death. Shea visited the jail days after Epstein’s suicide and helped advise the attorney general as Barr shook up the agency’s leadership, removing its acting director.

Shea, who begins his new role on Feb. 3, replaces Jessie Liu, who has been nominated to become the undersecretary for terrorism and financial crimes at the Treasury Department, as the Trump administration imposes economic sanctions as a national security tool. The attorney general said Liu had “served with distinction” as U.S. attorney.

Barr had nominated Liu to become the associate attorney general, the third-highest job in the department, overseeing civil litigation, but she withdrew from consideration after encountering opposition on the Republican-led Senate Judiciary Committee because of her past membership in a lawyers’ group that has supported abortion rights.

Liu would be first U.S. attorney to assume the role at Treasury. When she was U.S. attorney, her office brought several sanctions-related cases and issued a warrant to seize an Iranian supertanker caught in a diplomatic standoff because of violations of U.S. sanctions, money laundering and terrorism statutes.