The scandal over the firing of U.S. attorneys has just claimed another casualty. Mike Elston, the chief of staff to outgoing Deputy Attorney General Paul McNulty, is resigning effective next week.

Elston was deeply involved in the firing of federal prosecutors last year and -- by all appearances -- tried to hide the truth about what happened afterward by silencing the U.S. attorneys who were forced out. As the Associated Press reports, several of the ousted prosecutors said they received phone calls from Elston in which they believed he was offering them a threatening sort of quid pro quo: They don't talk about the circumstances of their firings, and the Justice Department wouldn't trash them in public. Elston has denied that he meant to threaten anyone.

Elston has also been implicated in the pursuit of trumped-up voter fraud cases and is the target of charges that he politicized the Department of Justice's hiring of entry-level attorneys by striking from consideration candidates who had any evidence of liberal leanings on their résumés.

Elston becomes the fifth Justice Department official to leave under the cloud of the scandal. Kyle Sampson, who served as Gonzales' chief of staff, and Mike Battle, who ran the Executive Office for U.S. Attorneys, resigned in March. Monica Goodling, who was Gonzales' White House liaison, left in April. And McNulty, who will testify before Congress next week, resigned in May.