Investigators found and seized at least six additional classified documents from President Joe Biden’s home in Wilmington, Delaware, on Saturday. The documents mark the fourth round of classified information discovered in Biden’s possession at his home or in his office that come from his time as vice president during the Obama administration, with some even coming from his tenure as senator.

Why did the search for classified documents happen in Biden’s home?

The 13-hour search took place after the president’s lawyers sought to provide access “in the interest of moving the process forward as expeditiously as possible,” said Biden’s attorney, Bob Bauer, The New York Times reported.

What we know about the investigation into Biden’s classified documents

A special counsel was appointed to investigate the documents for Biden’s case. Joseph D. Fitzpatrick, an assistant attorney spokesman for the counsel, said the search was “planned” and “consensual,” per the Times.

The Presidential Records Act requires that Biden should have sent the documents to the National Archives once his tenure ended in the Senate and the Obama administration, respectively, according to CNN.

Sen. Joe Manchin, D-W.Va., told The Associated Press that Biden “should have a lot of regrets. ... You just might as well say, ‘Listen, it’s irresponsible.’”

Six more classified documents found in Biden’s Delaware home

Both Biden and former President Donald Trump are currently under investigation for the mishandling of classified documents following an end to an administration.

Is there a difference between the Trump search and Biden search for classified docs?

When the Department of Justice suspected Trump had classified documents from his time as president, Trump refused to hand over any information or allow for a search. This prompted a warrant to check the safe at his Mar-a-Lago hotel that contained 184 classified documents.

“It is outrageous that either occurred. But the reaction by the former president and the current president could not be in sharper contrast,” Sen. Dick Durbin, D-Ill., said, according to AP.

Special master asks Trump for proof that the FBI planted documents at Mar-a-Lago