Defense lawyers for Don Blankenship alleged this afternoon that the federal government may have destroyed records that are important to the former Massey CEO’s case.

Bill Taylor, Blankenship’s lead defense lawyer, pointed to a statement that former Massey ventilation supervisor Bill Ross gave during a public records lawsuit several years ago against MSHA, that his former secretary at the agency told him documents from the ventilation department had been destroyed.

Defense layers apparently made a motion about the issue Wednesday, but the precise nature of that motion was unclear because it was made during a private bench conference.

After sending jurors out of the courtroom for a break, U.S. District Judge Irene Berger questioned Ross briefly about the matter. Taylor later explained to the judge that the controversy relates to a history of methane “outbursts” at the Upper Big Branch mine during the disaster probe, then-MSHA district manager Bob Hardman discovered records about those incidents slipped under his door.

Blankenship argues the mine disaster was caused by an uncontrollable methane outburst. Four independent and government investigations have disagreed with that argument — and Berger has said the cause of the disaster isn’t at issue in Blankenship’s trial.

Taylor, though, said that the Ross statement in Massey’s lawsuit against MSHA raises questions about whether documents the defense is entitled to were destroyed. Taylor noted that the defense has repeatedly complained that MSHA has not complied with the defense’s document request.