The head of the Justice Department's beleaguered Public Integrity unit is stepping down.

William Welch, who supervised the department's botched prosecution of former Alaska senator Ted Stevens, will remain with DOJ but return to Massachusetts, the Washington Post reported yesterday.

The unit was harshly criticized after Attorney General Eric Holder abandoned the case against Stevens, citing numerous missteps by prosecutors, mostly relating to failures to share evidence. The department's internal ethics unit is probing Welch and five other prosecutors from the unit in connection to the missteps, as is a special prosecutor appointed by Judge Emmet Sullivan, who heard the Stevens case.

That hasn't been the only recent black eye for the unit. Last week, a mistrial was declared in the corruption trial of Kevin Ring, one of the few defendants associated with the Jack Abramoff scandal to go to trial. In an interview with TPMmuckraker, one veteran Washington defense lawyer called it "a setback for Public Integrity."