NEW YORK (AP) Mounds of paper piled on his desk. Framed magazine covers and keepsakes lining the walls. One of Shaquille ONeals giant sneakers displayed alongside football helmets, boxing belts and other sports memorabilia, crowding his Trump Tower office and limiting table space.

Well before he entered politics, former President Donald Trump had a penchant for collecting. And that lifelong habit combined with his flip disregard for the rules of government record keeping, his careless handling of classified information, and a chaotic transition born from his refusal to accept defeat in 2020 have all culminated in a federal investigation that poses extraordinary legal and political challenges.

The search of Trumps Mar-a-Lago club earlier this month to retrieve documents from his White House years was an unprecedented law enforcement action against a former president who is widely expected to run for office once again. Officials have not revealed exactly what was contained in the boxes, but the FBI has said it recovered 11 sets of classified records , including some marked sensitive compartmented information, a special category meant to protect secrets that could cause exceptionally grave damage to U.S. interests if revealed publicly.

Why Trump refused to turn over the seized documents despite repeated requests remains unclear. But Trumps flouting of the Presidential Records Act, which outlines how materials should be preserved, was well documented throughout his time in office.

He routinely tore up official papers that later had to be taped back together . Official items that would traditionally be turned over to the National Archives became intermingled with his personal belongings in the White House residence. Classified information was tweeted, shared with reporters and adversaries even found in a White House complex bathroom.

John Bolton, who served as Trumps third national security adviser, said that, before he arrived, hed heard there was a concern in the air about how he handled information. And as my time went on, I could certainly see why.

Others in the Trump administration took more care with sensitive documents. Asked directly if he kept any classified information upon leaving office, former Vice President Mike Pence told The Associated Press on Friday, No, not to my knowledge.