WASHINGTON — A government accountability group is asking the Senate committee that heard testimony this summer from Chad Wolf, President Donald Trump's pick for acting Homeland Security Secretary, to refer Wolf for investigation by the Justice Department over alleged false claims to Congress.

The group, Restore Public Trust, said in a letter sent to the Senate Homeland Security and Government Affairs Committee on Thursday that Wolf "provided false testimony" to the committee when he claimed he did not help develop the policy that resulted in over 2,800 migrant children being separated from their parents in 2018.

The letter cites NBC News reporting on internal emails that show Wolf including family separation on a list of 16 policy recommendations to curb undocumented immigrants, including asylum seekers, from crossing into the U.S. that he sent to the Justice Department for approval in December of 2017.

Click here to read the letter.

In his list of recommendations, Wolf suggested the Trump administration "announce that DHS is considering separating family units, placing adults in detention and placing minors under the age of 18 in the custody of HHS as unaccompanied alien children." Those exact details became reality in May and June of 2018.

Click here to read the emails.

Wolf testified before the committee in June of this year as part of the confirmation process to become the undersecretary for strategy, policy and plans, a position he served in on an acting basis because he was never confirmed.

During the hearing, Sen. Jacky Rosen, D-Nev., asked Wolf if he helped develop the family separation policy, known as zero tolerance, that then-Attorney General Jeff Sessions announced in the spring of 2018.

"No ma'am," Wolf told Rosen. "We were given direction both through an executive order and the attorney general's zero tolerance policy at the time. The discussions that were underway at the Department at that time were operational."

Rosen then asked, "Let me ask it this way, as (Nielsen's) chief of staff then, how did you become aware of this policy?" referring to Wolf's role as chief of staff to then-DHS Secretary Kirstjen Nielsen.

"Through discussions with staff, leading up to the attorney general's announcement, I believe in April of 2018," Wolf said.

In addition to the NBC News reporting on the list of policy options Wolf sent to the Justice Department, Restore Public Trust referenced Wolf's schedule from March 2018, which indicates he participated in several meetings and phone calls discussing what became the family separation policy.

"In light of the evidence, it appears Mr. Wolf made a deliberate attempt to mislead the committee about his role in developing the family separation policy in violation of the prohibition against making false statements to Congress," the letter from Restore Public Trust said.

The group asked the committee to refer the matter to the Justice Department for further investigation into "whether and the extent to which he may have provided false testimony to the committee."

Heather Swift, a spokeswoman for DHS, said Wolf did not lie to Congress and his role in the policy was merely that of a diligent chief of staff.

"Mr. Wolf's job as chief of staff was to collect information from experts, provide the options to the secretary to allow her to make decisions on behalf of the Department. To suggest that he single-handedly conjured up and implemented more than a dozen tactics affecting multiple agencies and Departments is beyond conspiracy theory. It's wishful thinking by hacks hell-bent on stopping the progress the president has made at the border," Swift said in a statement to NBC News.