Walt Nauta, an aide to former President Trump, has been indicted along with the former president, according to the federal indictment unsealed Friday. 

The 38th count in the indictment against Trump alleges Nauta made false statements and representations during a voluntary interview with the FBI on May 26, 2022. 

Specifically, the government alleges he made a knowingly false statement when he said he did not know how the boxes were kept and moved, when he had in fact observed and moved them to various locations.

According to the indictment, Nauta was asked during the interview if he was "aware of any boxes being brought to [Trump's] home." "No," he responded.

He was also asked if he had any information about where the boxes were kept, whether they were stored or locked up.

"I wish, I wish I could tell you, he responded. "I don't know. I don't — I just honestly don't know."

These statements, prosecutors say, were lies. The content in the indictment that Nauta did know because "Nauta himself...had moved the boxes."

Nauta is named a co-conspirator in the case, and has been a key witness in the investigation led by special counsel Jack Smith into the handling of classified documents after Trump left office. 

Earllier Friday, former President Trump said in a social media post that Nauta had been indicted. 

"I have just learned that the 'Thugs' from the Department of Injustice will be Indicting a wonderful man, Walt Nauta, a member of the U.S. Navy, who served proudly with me in the White House, retired as Senior Chief, and then transitioned into private life as a personal aide," Trump posted on Truth Social. "He has done a fantastic job! They are trying to destroy his life, like the lives of so many others, hoping that he will say bad things about 'Trump.' He is strong, brave, and a Great Patriot. The FBI and DOJ are CORRUPT!"

Trump has been charged with 37 counts in the indictment involving the retention of national defense information, conspiracy and obstruction.

Nauta was seen at Mar-a-Lago moving boxes in security camera footage that has become a key part of the FBI investigation into Trump's handling of presidential records, according to one source. 

A former White House culinary worker and Navy veteran, Nauta told investigators last year that the former president had directed him to move the boxes to a different location as the federal investigation was underway. 

Multiple sources close to the investigation told CBS News that prosecutors focused on Nauta's interactions with the boxes, but talks between his legal team and the Justice Department stalled after prosecutors took a more aggressive approach. 

Robert Legare and Melissa Quinn contributed to this article.

Kathryn Watson

Kathryn Watson is a politics reporter for CBS News Digital based in Washington, D.C.