A powerful Republican senator who abruptly resigned last year is being investigated for his role in a conspiracy to bribe a judge presiding over multimillion-dollar lawsuit against a relative.

Former Senate Majority Leader Trent Lott of Mississippi may have knowingly played a role in a 2006 plot to influence a state circuit court judge to rule in favor of Lott’s brother-in-law, millionaire attorney Richard Scruggs, who made his fortune from asbestos litigation and brokering multibillion-dollar settlements with tobacco companies in the 1990s.

Scruggs, a major Democratic Party donor, was indicted late last year for offering to pay the judge $50,000 to rule in his favor in a lawsuit relating to Hurricane Katrina insurance claims. The judge (Henry Lackey) immediately reported the offer to federal authorities, however.

Just two days before the indictment, Lott, who served 15 years in the U.S. House before serving nearly a decade in the Senate, shocked many by unexpectedly resigning from Congress. He has since joined a Washington lobbying firm.

Federal prosecutors in Oxford Mississippi are also looking into a separate case in which Lott may have offered to recommend a different state judge (Robert Delaughter) for a seat on the federal bench if he ruled in favor of Scruggs.