A top prosecutor in the Suffolk District Attorney’s Office has his job back after an independent investigation found he “did nothing improper” regarding a decades-old murder conviction.

Mark Lee returns to office as assistant district attorney after being placed on paid leave last November amid allegations he withheld information in a case involving the 1992 second-degree murder conviction of Robert Foxworth.

“Mark’s character, prosecutorial experience and dedication to the people of Suffolk County equip him well for this extremely important position,” District Attorney Kevin Hayden said in a statement Thursday. “We welcome Mark back to the office and we look forward to his strong leadership of the homicide unit.”

Foxworth spent nearly three decades in prison for a 1991 murder in Dorchester before being exonerated in December 2020.

The months-long suspension came after Foxworth’s attorney filed a complaint with the Massachusetts Office of the Bar Counsel alleging Lee for withholding evidence that Foxworth did not commit the murder, starting as early as 2007.

Independent investigator Comprehensive Investigations and Consulting concluded the information Lee was accused of not bringing forward “had been known to Foxworth and his counsel for many years”, and that information did not lead to his dismissal, according to officials.

CIC also found Foxworth’s team did not share the information that ultimately led to his dismissal with the Suffolk County District Attorney’s Office “for many years.”

“The report showed that when Foxworth’s counsel finally brought forward that information, which involved a recantation by an eyewitness, Lee played an instrumental role in the ensuing investigation,” the release states. “The report found that Lee led the interview of the eyewitness and that his assessment of the witness’s credibility proved pivotal in the dismissal of Foxworth’s charges.”

The state Board of Bar Overseers is conducting its own investigation which remains in progress.

CIC conducted 23 interviews and reviewed 84 documents and 54 exhibits.

Hayden promoted Lee from deputy chief of homicide, a role he had held since 2008, to the chief of the homicide unit upon his return to the office. Lee helped play a lead role in the prosecution of former Patriots player Aaron Hernandez’s murder cases.

“We have always been confident that the office’s actions in the Foxworth case were proper, ethical and instrumental in addressing the problematic 1992 trial and conviction,” Hayden said. “We’re pleased that this investigation and report soundly rejects any suggestion of improper conduct by Mark Lee, and we’re glad to have this matter resolved.”