US lawmakers sought answers from the White House on Friday following revelations that three men accused of having orchestrated the 9/11 terror attacks had been spared the death penalty after striking a plea deal with military prosecutors.

On Wednesday, a letter to the families of 9/11 victims revealed that Khalid Shaikh Mohammed, Walid Bin ‘Attash, and Mustafa al Hawsawi had pled guilty to the attacks that claimed nearly 3,000 lives on September 11, 2001.

In the letter, prosecutors wrote:

In exchange for the removal of the death penalty as a possible punishment, these three Accused have agreed to plead guilty to all of the charged offenses, including the murder of the 2,976 people listed in the charge sheet, and to be later sentenced by a panel of military officers.

The letter also noted that as part of the deal, the three men had agreed to answer questions posed by the victims’ family members with respect to their roles in and motivations for planning the attacks.

On Friday, the House Oversight Committee announced a probe, spearheaded by Chairman James Comer, a Republican lawmaker from Kentucky. The aim, Comer wrote, is to shed light on the Biden Administration’s potential involvement in the negotiation process and the rationale behind the decision to offer plea deals in this high-profile case.

Comer’s complaint cited claims by the White House Security Council that Biden had played no role in the negotiations, which were approved by senior Pentagon officials.

This sentiment was reiterated Thursday by US National Security Advisor Jake Sullivan, who said in a briefing:

The president had no role. The vice president had no role. I had no role. The White House had no role. And we were informed yesterday — the same day that they went out publicly that this pretrial agreement had been accepted by the convening authority.

Comer expressed skepticism about this claim:

That White House officials and you, as President and Commander in Chief, would seek to distance your Administration from this decision is understandable given how absurd it is, but it is far from believable or appropriate.

He also raised concerns about what he sees as the lack of transparency surrounding the deal. “The specific terms of the pre-trial agreements remain undisclosed to the public or families of the victims,” Comer noted, adding that the decision “signals to our enemies that the United States is reluctant to pursue full justice against those who attack our nation.”

In the military prosecutors’ letters to victims family, they addressed the controversial nature of a plea deal in such a case, stating:

We recognize that the status of the case in general, and this news in particular, will understandably and appropriately elicit intense emotion, and we also realize that the decision to enter into a pre-trial agreement will be met with mixed reactions amongst the thousands of family members who lost loved ones. The decision to enter into a pre-trial agreement after 12 years of pre-trial litigation was not reached lightly; however, it is our collective, reasoned, and good-faith judgment that this resolution is the best path to finality and justice in this case.

In informing the White House of the decision to investigate, Comer cited the spouse of a 9/11 victim who expressed some of what the prosecutors had anticipated:

I am angry and disappointed that enemy combatants who killed thousands of Americans in our homeland are now able to exploit the U.S. judicial system to their benefit, receiving support from American taxpayers for shelter, food, and healthcare for the rest of their lives.