The FBI searched Biden's old office after his lawyers discovered a cache of classified documents there, CBS reported.
Biden's representatives cooperated with the search in mid-November, and the FBI did not seek a warrant.
The DOJ also searched Biden's home earlier this month, after a second batch of records was discovered there.
The FBI searched President Joe Biden's old office at the Penn-Biden Center last year, CBS News reported. Agents carried out the search in mid-November, after Biden's aides discovered 10 classified documents at the office dating back to his time as vice president.
CBS reported that the FBI did not seek a warrant to search the office and that Biden's representatives cooperated with the sweep. Although the documents' discovery and the FBI's search took place in November, the White House did not publicly announce it until earlier this month.
CBS' reporting is the latest twist in an ongoing controversy involving both Biden and former President Donald Trump's mishandling of national security information - both of whom now face separate special counsel investigations.
After Biden's lawyers discovered the initial cache of classified documents in his office in November, they immediately notified the White House counsel's office, which contacted the National Archives.
The documents were turned over to the Archives soon after, and the FBI began investigating that same month whether classified information had been improperly handled. Attorney General Merrick Garland appointed John Lausch, a Trump-era US attorney in Chicago, to handle the inquiry.
In December, Biden's legal representatives told Lausch that they had uncovered additional classified materials in the garage at Biden's personal residence in Delaware.
On January 12, after reports surfaced that a second batch of classified documents had been found after the initial sweep of Biden's old office, Garland took the extraordinary step of appointing a special counsel to investigate Biden's handling of classified information. The move put Garland and the Justice Department in the unprecedented position of overseeing two parallel special counsel investigations into the current and former president's management of government records.
On January 21, Biden's personal attorney Bob Bauer announced that the Justice Department had also searched the president's Delaware home and discovered half a dozen documents marked classified. Neither Biden nor first lady Jill Biden were present during the search, which lasted 13 hours.
Trump, for his part, has repeatedly pointed to the way the feds have handled the Biden investigation as being tainted by political bias, alleging that Biden has been treated with more leniency than he was when the FBI executed a search warrant at Mar-a-Lago last summer.
"When is the FBI going to raid the many homes of Joe Biden, perhaps even the White House?" Trump wrote on his Twitter-esque website, Truth Social.
But legal experts and DOJ veterans caution against conflating the two inquiries, noting that Biden's team immediately notified the archives and has been cooperating with the DOJ, while Trump refused to turn over troves of sensitive government records over 18 months of back-and-forth with US officials.
As new details continued spilling out about the DOJ's investigations into Trump and Biden, CNN also reported last week that classified documents were discovered at former Vice President Mike Pence's home in Indiana.
According to the report, the FBI is investigating the materials and reviewing how they ended up at Pence's residence. The former vice president's team found two boxes that included classified records and four boxes that contained potential presidential records but believed they were courtesy copies of documents the Archives already possessed, according to Politico. Pence sent the six boxes to NARA last week.