Exclusive: Former White House official told federal prosecutors Trump knew of proper declassification process and followed it while in office

A key former White House official was interviewed earlier this year by special counsel prosecutors investigating the handling of classified materials by both former President Donald Trump and President Joe Biden, CNN has learned.

The former career official, who was in charge of advising the Trump and Obama administrations on the declassification process, is the only known witness to be interviewed by both teams of prosecutors investigating Trump and Biden.

During those voluntary interviews, the former official told CNN there was a distinct difference in the line of questioning from prosecutors in the two probes.

While prosecutors in the Trump case aggressively focused on any first-hand interactions with the former president, including conversations about how to properly declassify documents, prosecutors in the Biden case were more concerned with the mechanics of packing and moving boxes into Biden's home in Delaware as his time as vice president came to an end.

"You wouldn't expect it to match the intensity, and it didn't," the former official said comparing the interview with Biden investigators to discussions with prosecutors in the Trump probe.

Speaking to CNN on condition of anonymity, the former official said he told federal prosecutors that Trump knew the proper process for declassifying documents and followed it correctly at times while in office.

The interview with the former official, which has not been previously reported, is the latest indication that prosecutors are seeking evidence suggesting Trump understood the process for declassifying documents. That could undercut Trump's claims that he automatically declassified everything he took with him to Mar-a-Lago.