Washington  — The FBI conducted two searches of the University of Delaware as part of the Justice Department’s probe into the handling of documents with classified markings from President Joe Biden’s time as vice president, three U.S. officials confirmed to CBS News. 

The searches were conducted within the last month, the first search took place toward the end of January, and the second at the beginning of February, according to a source familiar with the investigation. FBI personnel removed multiple boxes from the premises. The documents removed did not have classified markings on them but included materials that required more scrutiny, the source told CBS News.  

Justice Department officials, as well as the FBI, also interviewed a University of Delaware archivist who handled Mr. Biden’s material, the source said.

The University of Delaware, Mr. Biden’s alma mater, is home to an institute named for the president, and the school’s library houses a collection of his senatorial papers and records. CBS News’ attempt to reach the curator of the collection was unsuccessful Wednesday night. 

The university was the fourth location associated with the president where searches have been carried out by federal investigators.

CNN was first to report the FBI searches at the University of Delaware. 

Lawyers for the president first discovered Obama-era classified documents in early November at The Penn Biden Center, a think tank used by Mr. Biden before declaring his candidacy for president in 2019. The FBI has also carried out searches at Mr. Biden’s homes in Wilmington and Rehoboth Beach, Delaware.

The White House, a spokesperson for President Biden’s personal attorney, and a spokesperson for the University of Delaware declined to comment, referring inquiries to the Justice Department. The Justice Department also declined comment. 

In November, one of Biden’s personal attorneys, Patrick Moore, discovered roughly 10 documents with sensitive markings at the Penn Biden Center in Washington, D.C. Some were marked top secret. The president’s attorneys notified the National Archives about the revelation, which prompted the Archives to refer the matter to the Justice Department. The FBI carried out a consensual search of the think tank that month. 

The following month, on Dec. 20, Mr. Biden’s personal attorneys uncovered additional records marked classified in Biden’s home in Wilmington, Delaware, which were turned over to the FBI for review.  

Attorney General Merrick Garland appointed former U.S. Attorney Robert Hur as special counsel to investigate the matter on Jan. 12, 2023. That same day, President Biden’s personal attorneys alerted the Justice Department to another classified document discovered in his Willmington residence. On Jan. 20, the FBI conducted a 13-hour search of the president’s Wilmington home. 

According to the president’s attorney, six items consisting of documents with classification markings and surrounding materials were ultimately collected, some of which dated back to the president’s service in the Senate and some that were from his tenure as vice president. 

A search of the president’s Rehoboth Beach home earlier this month by the FBI did not uncover any sensitive records. 

University of Delaware representative Peter Bothum told CBS News on Jan. 16, “No vice presidential materials have been sent to or are stored at the university.” At that point, he said no searches had been conducted for documents at the university.

Revelations of sensitive records from Mr. Biden’s time as vice president arose amid an ongoing federal investigation into the handling of classified documents retained by former President Donald Trump after his presidency. 

Special counsel Jack Smith is probing allegations that restricted records were mishandled during Trump’s transition from the White House and that individuals tied to Trump may have obstructed the investigation. In August, the FBI executed a search warrant at Trump’s Mar-a-Lago residence in Florida after a year-long legal battle to retrieve all missing documents. 

Trump’s vice president, Mike Pence, was found to have  classified documents after leaving office. Earlier this month, his attorneys discovered records with classified markings and handed them over to the Justice Department for review. Last week, an FBI search at Pence’s home uncovered an additional classified record. 

Like the Biden searches, the search at Pence’s home was consensual.

Last week, the National Archives released emails revealing that documents at the Boston office of Mr. Biden’s attorney had been handed over to officials with the Archives in November.

Gillian Morley contributed reporting.

Adriana Diaz

Adriana Diaz is a CBS News correspondent based in Chicago and is the anchor of Saturday’s edition of the “CBS Weekend News.”