WASHINGTON – Two Senators on Tuesday called for an independent investigation of whether retired Adm. Sandy Winnefeld misled Congress about military sexual assault prosecutions.

Sens. Kirsten Gillibrand, D-N.Y., and Chuck Grassley, R-Iowa, requested the probe in a letter to President Barack Obama, saying the former vice chairman of the Joint Chiefs of Staff might have inaccurately characterized and omitted information about such assault cases while testifying under oath and in a letter to lawmakers in 2013.

The call for an investigation is fallout from a report released Monday by Protect Our Defenders, a nonprofit advocate for sex assault victims. The group, along with an Associated Press investigation, found Winnefeld exaggerated the military’s role in prosecuting the cases in order to block Senate reform legislation aimed at stripping some power from commanders.

“The allegations in the Protect Our Defenders report and the AP article include providing inaccurate information to a congressional committee, misleading the Congress, and undermining efforts to make critical reforms to a broken system,” Gillibrand and Grassley wrote to Obama. “Due to the very serious nature of these allegations, we request that you direct an independent investigation into this matter.”

Gillibrand led the political fight in 2013-2014 to remove the decision to prosecute sex assaults from commanders, or so-called convening authorities. But the proposal was shot down by other lawmakers such as Sen. Claire McCaskill, D-Mo., who were swayed by Winnefeld’s argument.

Winnefeld testified in 2013 before the Senate Armed Services Committee that civilian authorities were refusing to prosecute sex assault cases involving military personnel and the cases were only pursued because commanders insisted.

Fewer sex assault cases would be prosecuted if Congress removed the power of commanders to intervene and instead gave the decision to military lawyers, the admiral said during the testimony.

After the hearing, he sent a widely quoted letter to lawmakers citing 93 such cases to back his argument.

Winnefeld, who retired in July, could not be immediately reached for comment.

The number of cases was repeated by McCaskill and others during the debate over Gillibrand’s bill, which was eventually defeated by a narrow margin in 2014.

On Monday, Protect Our Defenders found that in the majority of sex assault cases cited by Winnefeld civilian authorities had not declined to prosecute.

“In two-thirds of cases, there was no sexual assault allegation, civilian prosecutors never declined the case, or the military failed to prosecute for sexual assault,” according to the group’s report.

Furthermore, there was no evidence in 81 of the cases that a commander insisted that the military prosecute, the group found.

“This disingenuous effort on the part of the Pentagon served only to distract from the continued failures of the command-based military justice system,” Protect Our Defenders stated in a release.

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