The New York Times reported Thursday that federal prosecutors are initiating a grand jury inquiry into the role of former President Donald Trump and other White House employees in the mishandling of secret data, citing “two people briefed on the subject.”

The investigation began after the National Archives discovered that 15 boxes containing government papers were removed from the White House in January 2021 and delivered to Trump’s Mar-a-Lago estate in Florida.

Federal authorities were only in the preliminary stages of investigating in April; however, authorities have now reportedly decided to take action. “In recent days … prosecutors [have] issued a subpoena to the National Archives and Records Administration to obtain the boxes of classified documents,” writes the Times. There have also been requests to interview other White House workers.

Discovering the truth of what happened with the classified documents might be challenging. Authorities would have to show that Trump and other White House officials “knowingly and intentionally broke the law” by proving the people involved understood that taking the materials out of the White House was illegal.

In the past 15 months since Trump left office, the former president has faced many legal problems. “The decision to move forward with an investigation into the classified documents could draw the [Justice Department] even deeper into the country’s political tensions,” writes the Times.