Brian Kelly. Brian Kelly.

The billionaire founder of a prescription opioid manufacturer who was indicted on federal fraud and racketeering charges last month has hired the Nixon Peabody partner who successfully prosecuted Boston mobster James “Whitey” Bulger as his defense attorney.

The attorney, Brian Kelly, was retained by Insys Therapeutics Inc. owner John Kapoor four days after Kapoor’s arrest in late October.

Kelly was part of the team that prosecuted Bulger, a former fugitive who was convicted in August 2013 on racketeering, money laundering and extortion charges as well as participation in 11 murders, and sentenced to two terms of life imprisonment.

The U.S. Department of Justice charged Kapoor with Racketeer Influenced and Corrupt Organizations Act conspiracy, as well as other felonies, including conspiracy to commit mail and wire fraud and conspiracy to violate the federal Anti-Kickback Statute. The indictment alleges that Kapoor, 74, of Phoenix, and his co-defendants—the former Insys CEO and other former executives—bribed doctors to write large numbers of prescriptions for the Insys drug Subsys, a fentanyl-based oral spray medication meant to treat only patients with cancer pain.

The indictment also alleges that the defendants defrauded insurers who were reluctant to approve payment of the drug for non-cancer patients. They did so, according to the government, by directing employees to disguise the identity and location of their employer and misrepresenting patient diagnoses, the type of pain being treated and the patient’s course of treatment with other medications.

Although Kapoor was arrested in Phoenix, the charges are pending in the U.S. District Court for the District of Massachusetts and include former Insys CEO Michael Babich and five other ex-company executives and managers. Those six defendants were indicted last December.

Acting U.S. Attorney William D. Weinreb of the District of Massachusetts said at the time of the indictment that the “arrest and charges reflect our ongoing efforts to attack the opioid crisis from all angles. We must hold the industry and its leadership accountable—just as we would the cartels or a street-level drug dealer.”

Kelly could not be reached for comment on the Kapoor case or his representation of him.

A Long Career as a Prosecutor

Kelly was part of the team that prosecuted Bulger, a fugitive for more than 16 years who was arrested in California in 2011. After an eight-week trial in Massachusetts, Bulger was convicted on 31 counts after a decades-long pursuit by the FBI and federal prosecutors and other law enforcement agencies.

For Kelly, who left the government for Nixon Peabody in December 2013, the Bulger trial and sentencing were the culmination of his career with the U.S. Attorney’s Office in Boston, which he joined in 1991 and left as chief of the public corruption and special investigations unit.

Kelly told The Boston Globe in 2013 upon his resignation from the U.S. Attorney’s Office that his interest in the law was spurred by the brutal murder of a teenage friend when Kelly was 11 years old. He said in the interview that he was outraged that the young killer served just a year in prison for the crime. He told the Globe that his move to Nixon Peabody was due in large part to mounting tuition costs with two children in college and one headed there shortly.

Kelly also worked as a defense attorney and federal prosecutor in San Diego before moving back to Boston. He was reared in a Boston suburb and attended Dartmouth College and the University of Pennsylvania Law School, according to his LinkedIn profile.

Although arguably best known for his prosecution of Bulger, Kelly was involved in other high-profile cases during his time as a federal prosecutor in Boston. These, according to the Globe article, included efforts to recover $500 million of artwork stolen from the Isabella Stewart Gardner Museum in 1990, and charges of financial fraud involving Boston’s Big Dig project, a massive, years-long highway construction project.

At Nixon Peabody, where Kelly started in January 2014, he is a partner in the firm’s government investigations and white-collar defense practice. He defends corporations and individuals in state and federal investigations involving health care fraud, insider trading, white-collar criminal defense and regulatory compliance, according to his firm bio.

And he’s already made the news there: Kelly was the outside lawyer representing Boston’s Thornton Law Firm in a Federal Election Commission complaint about whether the personal injury firm skirted campaign finance laws.

The other defendants in the Kapoor case are represented by: Clements & Pineault; Demeo; Donnelly, Conroy & Gelhaar; Fitch Law Partners; Hogan Lovells; King & Spalding; Mitchell Stein Carey Chapman; Robert L. Sheketoff; Weil, Gotshal & Manges; and White & Case.