The National Archives and Records Administration last month got a hold of multiple boxes containing documents and records from the Trump White House, after former President Donald Trump “improperly removed” the boxes and brought them to his Mar-a-Lago residence, The Washington Post reports. The boxes should have been handed over to the Archives.

Though advisers deny bad intent, the “recovery of the boxes … raises new concerns about [Trump’s] adherence to the Presidential Records Act, which requires the preservation of memos, letters, notes, emails, faxes and other written communications related to a president’s official duties.”

The boxes contained contained “mementos, gifts, letters from world leaders and other correspondence,” advisers added. Among the contents were communications with North Korea’s Kim Jong Un — which Trump once called “love letters” — as well as a letter left for him by former President Barack Obama, the Post reports.

“The only way that a president can really be held accountable long term is to preserve a record about who said what, who did what, what policies were encouraged or adopted,” presidential historian Lindsay Chervinsky told the Post, “and that is such an important part of the long-term scope of accountability — beyond just elections and campaigns.”

To note is that all recent administrations have also violated the Presidential Records Act from time to time. The Archives have also had to previously retrieve documents from other White Houses after a president has left office. That said, Trump is still an anomaly “in the scale of the records retrieved from Mar-a-Lago,” the Post writes.

Said one person close to the matter: “NARA has never had that kind of volume transfer after the fact like this.”