Updated

House Democrats on Wednesday requested an immediate probe into "suspicious behavior" and access that was said to be given to visitors at the U.S. Capitol a day before the riot.

The 34 lawmakers, in a letter, urged the Capitol Police and the acting House and Senate sergeants-at-arms to look into the matter. Rep. Mikie Sherrill, D-N.J., was joined by others who said they noticed an unusually high number of outside groups in the complex on Jan. 5. 

"This is unusual for several reasons, including the fact that access to the Capitol Complex has been restricted since public tours ended in March of last year due to the pandemic," the letter stated, according to Politico. The lawmakers said the tours "were so concerning" that they were reported "to the Sergeant at Arms" that same day, Jan. 5.

NJ REP. SHERRILL: UNIDENTIFIED LAWMAKERS LED APPARENT 'RECONNAISSANCE' TOURS PRIOR TO CAPITOL ATTACK

Rep. Mikie Sherrill, D-N.J., walks up the House steps for a vote in the Capitol on Thursday, Sept. 17, 2020. (Photo By Bill Clark/CQ-Roll Call, Inc via Getty Images)

Rep. Mikie Sherrill, D-N.J., walks up the House steps for a vote in the Capitol on Thursday, Sept. 17, 2020. (Photo By Bill Clark/CQ-Roll Call, Inc via Getty Images)

"The visitors encountered by some of the Members of Congress on this letter appeared to be associated with the rally at the White House the following day," the lawmakers wrote. "Members of the group that attacked the Capitol seemed to have an unusually detailed knowledge of the layout of the Capitol Complex. The presence of these groups within the Capitol Complex was indeed suspicious."

Among the requests made in the letter included whether there are logbooks of visitors that are regularly inspected and collected. They also asked security officials to provide information on the names of "Members or staff" who were part of the alleged tours. 

Sherrill, a former U.S. Navy helicopter pilot, said that members of Congress led apparent "reconnaissance" tours of the Capitol the day before the riot.

Sherrill made her comments during a roughly 13-minute video on Facebook, where she addressed her constituents about the steps that Congress will take to hold President Trump and "those responsible" accountable for allegedly inciting the riot. 

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The congresswoman didn't name any of the lawmakers or offer additional details into what qualified their actions to be "reconnaissance," during the video, according to the media company

Rep. Tim Ryan, D-Ohio, told reporters at the Capitol that he's heard of a couple of names of colleagues who potentially gave tours, but said he was going to wait to make sure "we get verification."

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Sherrill told Fox News on Wednesday: "We're requesting an investigation right now with certain agencies," without elaborating.