The House Oversight Committee, which is leading the impeachment inquiry into President Biden, is demanding that the Department of Justice hand over the classified documents Mr. Biden held onto after his vice presidency, as it seeks to determine if Mr. Biden was hoarding the documents in order to conceal an inappropriate, or unlawful, role in his son Hunter’s business affairs. 

“The Justice Department must provide Congress with unfettered access to these documents to determine if President Biden’s retention of sensitive materials were used to help the Bidens’ influence peddling schemes,” the chairman of the Oversight Committee, James Comer, said in a statement. The committee itself also said in a statement: “The American people deserve transparency about President Biden’s mental state.”

During an appearance on “Fox News Sunday,” Mr. Comer said that impeachment investigators believe there could be overlap between the classified materials Mr. Biden had squirreled away in his garage and at his University of Pennsylvania offices and Hunter Biden’s work abroad, during which the younger Mr. Biden traded on his father’s name to make money from foreign entities in China, Ukraine, and other countries. 

For months, Mr. Comer has been investigating with little success the foreign business dealings of Hunter Biden, his uncle James Biden, and other family members. The chairman believes that the classified documents found in the president’s home and at the Penn Biden Center — which contain information about American policy with respect to Ukraine and China — could offer insight into whether the then-vice president illegally took policy actions in order to help Hunter get business.

In October, Mr. Comer wrote to Mr. Hur to request access to the materials that had been found in the president’s personal residence and offices. “President Biden’s retention of certain classified documents begs the question as to why he kept these particular materials,” Mr. Comer wrote at the time. “Of the many classified documents he reviewed over his lengthy career, why did President Biden keep these specific documents in his home and office? The sensitive nature of the information contained in the documents may answer that question for the Committee, which is why we seek to review those materials.”

Now that Mr. Hur’s report has been released, Mr. Comer is redoubling his efforts to see the hoarded classified materials.

Hunter Biden and James Biden have made millions of dollars from business dealings in Ukraine and China, which both had pressing issues before the United States while the president was serving as vice president. Mr. Comer says he needs to know if Mr. Hur interviewed any Biden family members about whether the hoarded classified documents were in any way connected to these lucrative deals. 

“We have a lot of questions about Hur’s report beyond the fact that he stated the obvious with respect to the president’s mental capacity,” Mr. Comer says.

The White House spokesman for oversight and investigations, Ian Sams, said on Friday the White House has not made a decision on that matter. “It’s important to note that we’re dealing with classified materials … there are classification issues there,” Mr. Sams said at a press conference. “I don’t have an announcement on the release of anything.”

Mr. Comer says his upcoming interview with a former associate of Hunter Biden, Tony Bobulinski, could yield some answers for the impeachment inquiry. Mr. Bobulinski, who claims to have met with the president in 2017 — which the White House denies — worked with the first son on a joint venture with a now-shuttered Chinese energy company, CEFC. 

“Tony Bobulinski was privileged to a lot of information about just exactly what the Bidens were going to do with China,” Mr. Comer said of the upcoming interview, which will happen on Tuesday morning. 

A number of the documents found in the president’s home and in his private offices at Philadelphia and the nation’s capital included detailed information about his official actions as vice president with foreign counterparts from countries where his son was doing business. 

According to the appendix of Mr. Hur’s report, the documents that Mr. Biden retained included two memos about meetings and calls with the prime minister of Ukraine in December 2015, and a memo detailing his lunch plans with the then-president of Ukraine, Petro Poroshenko, in 2014.

There are also documents dated shortly before the 2012 election that lay out strategies for dealing with China in a second Obama term, as well as documents from early in the first term pertaining to issues in Afghanistan, Iraq, and Pakistan.