The special counsel tapped Wednesday to investigate possible links between Russia and the Trump 2016 campaign team has deep ties to Boston, where his work on several high-profile cases made clear his prosecutorial talents.
Robert S. Mueller III, 72, who went on to serve as FBI director from 2001 to 2013, first came to Boston in 1982 as an assistant US attorney.
“Bob is the quintessential prosecutor, very bright, focused, and tenacious in a search for the truth,” said Boston attorney A. John Pappalardo, who worked alongside Mueller in the US attorney’s office in Massachusetts.
“His long record in public service also illustrates that he is as fair and nonpolitical as he is tough and knowledgeable,” said Pappalardo, who is now a partner at the law firm Greenberg Traurig. “Bob is an outstanding choice.”
Mueller served in Boston under William F. Weld, the US attorney at the time, and led the office for more than a year when Weld took another job in the Justice Department.
Among reporters, Mueller was known as a tight-lipped prosecutor, routinely responding “no comment” when queried about cases.
He did, however, reflect on his tenure in government when he left the US attorney’s office, telling the Globe that “I love prosecuting, I love what I’ve done here.”
Those who know Mueller say he was driven by a career-long passion for the painstaking work of building successful criminal cases.
‘‘The management books will tell you that as the head of an organization, you should focus on the vision,’’ Mueller once said. But ‘‘for me there were and are today those areas where one needs to be substantially personally involved.’’
After leaving the US attorney’s office in 1988, Mueller went on to work at the Boston law firm Hill and Barlow.
He returned to the Justice Department the following year.
He served as head of the department’s criminal division in the George H.W. Bush administration, and returned to private practice in 1992, after Bush lost his reelection bid.
Mueller then went to work for the Boston firm of Hale & Dorr — which later merged with another firm to become part of Wilmer Cutler Pickering Hale and Dorr, or WilmerHale — before resuming his career as a prosecutor in 1995, serving as US attorney for the District of Columbia.
He became US attorney in San Francisco three years later with the backing of the state’s two Democratic senators.
Some of the biggest cases that Mueller prosecuted in Boston were investigated by the FBI, including the so-called Examscam case, involving a ring of police officers who stole civil service promotional exams and sold them to friends who cheated to advance to top jobs around the state.
He also prosecuted the highly publicized case of a German spy who paid $15,800 for classified information from a Navy civilian employee who worked for the FBI as a double agent.
Former US attorney Michael J. Sullivan, who worked closely with Mueller as FBI director, described Mueller as “a rock-solid professional” who is highly ethical and takes a no-nonsense approach to the task at hand. “He’s got a stellar reputation,” Sullivan said.
“I think he’s kind of universally recognized as somebody that will get the job done, get the job done well, and get the job done right.”
Mueller took office as FBI director in 2001, a week before the terrorist attacks of Sept. 11, and went on to spend the next 12 years leading the agency in its mission against terrorism. He was at the helm of the FBI when its agents captured the notorious South Boston gangster James “Whitey” Bulger in 2011 in Santa Monica, Calif.
Mueller also testified before the House Judiciary Committee in June 2013, two months before he stepped down as FBI director, about the investigation into the Boston Marathon bombings.
He said the FBI did a “thorough job” investigating Tamerlan Tsarnaev, one of the bombers, when Russian authorities alerted the agency in March 2011 of their belief that Tsarnaev was a terrorism threat.
But he blamed Russian authorities for failing to respond three times to an FBI request for follow-up evidence after the US-based investigation.
Tsarnaev died in a confrontation with police days after the April 15, 2013, bombings, which killed three people and wounded more than 260.
His younger brother, Dzhokhar, was convicted for his role in the attack and was sentenced to death. An appeal is pending.
After retiring from the FBI in 2014, Mueller rejoined WilmerHale, in its Washington office.
The Boston attorney Paul V. Kelly, who was hired as a prosecutor by Mueller in 1987 when he was acting US attorney in Boston and worked under him for a year, said:
“I have an incredible amount of respect for the guy. He’s as no-nonsense, hard-nosed, determined, ethical a prosecutor as you’ll ever find.
He described Mueller as apolitical, as well as smart, thorough, serious, and laser-focused.
“It’s rare that you see flashes of humor from Bob Mueller,” Kelly said. “He’s just a serious, committed individual — who, frankly, has an incredibly impressive track record of public service.”
Mueller is scheduled to deliver the commencement address at Tabor Academy, a private school in Marion, on May 29.
It was not clear on Wednesday whether he would still deliver his speech to the graduating class.