Day two of the hearings was dominated by the issue of unlawful influence, whether there was any outside pressure on the convening authority—the overseer of the military commission—to make certain judicial decisions in a certain way.

On February 5, Secretary of Defense Jim Mattis fired convening authority Harvey Rishikof and legal adviser Gary Brown and according to defense lawyers, the decision to fire Rishikof and Brown was because the two were exploring options for a plea deal that would allow the defendants of the 9/11 case to plead guilty in exchange for taking the death penalty off the table.

Today, William Castle, the Acting General Counsel of the Department of Defense during the time of the firing and the months leading up to it, testified in front of the court, facing hours of questioning from the defense team who set out to demonstrate that there was at least “some evidence” that the independent judicial judgement of Rishikof was compromised.

As part of Castle’s testimony, we learned more details that led to the decision to fire Rishikof, but it goes something like this:

Conversations between the prosecution and the defense team of Khalid Sheik Mohammed, the primary defender of the case and the accused “mastermind” behind 9/11, had progressed so far that the team had tendered a plea deal on August 15, his lead lawyer David Nevin said. According to Castle, Rishikof had reached out to the Department of Justice (DOJ) because Nevin’s team wanted to make sure that the DOJ would not charge Mohammed under different charges seeking the death penalty if this military commission reached the plea agreement.

While it was previously reported that at some point in mid-October then-Attorney General Sessions called Mattis’ in an effort to spike any pre-trial agreement (PTA), Castle’s testified today that he was in the room for that call and that Sessions had explicitly said “no deals” in reference the tentative deal.

The defense team argues that that call and Rishikof’s openness to a plea deal without the death penalty, ultimately led to his firing.

The prosecution and Castle, on the other hand, argue that Rishikof’s firing was because of other past conduct complaints with Rishikof and that he wouldn’t get on the same page with what Castle calls “same ships headed in the same direction at the same time,” frequently going around him as Acting General Counsel without any consultation for cohesion.

Also new with Castle’s testimony was the degree to which other individuals  were aware of the proposed plea deal. Everyone in the Office of General Counsel at the Pentagon was aware, Castle said.

Through the course of questioning, it was also revealed that the Army’s General Counsel James McPherson was originally going to be appointed as Rishikof’s successor as Convening Authority. Castle, however, talked with McPherson about the plea deals and after realizing that could violate rules about unlawful influence if McPherson were to take over, then rescinded that offer. Melinda Perritano is now the convening authority.

The defense team sought today to prove that there was at least “some evidence” that there was unlawful influence. Oral arguments on the issue, based on testimony, are expected Thursday. If the judge rules that there was unlawful influence, the burden would then shift to the prosecution to prove “beyond a reasonable doubt” that there was no unlawful influence.

If the judge ends up ruling that there was some unlawful influence, the defense team will surely argue that the death penalty should be taken off the table.