Federal Bureau of Investigation agents who executed a federal search warrant at Mar-a-Lago Monday were on the hunt for “classified documents relating to nuclear weapons,” according to an exclusive Washington Post report Thursday evening.

“Experts in classified information said the unusual search underscores deep concern among government officials about the types of information they thought could be located at Trump’s Mar-a-Lago Club and potentially in danger of falling into to the wrong hands,” the Post adds.

“If that is true, it would suggest that material residing unlawfully at Mar-a-Lago may have been classified at the highest classification level,” David Laufman, the former chief of the Justice Department’s counterintelligence section, told the Post. “If the FBI and the Department of Justice believed there were top secret materials still at Mar-a-Lago, that would lend itself to greater ‘hair-on-fire’ motivation to recover that material as quickly as possible.”

This latest development into Donald Trump’s improper and possibly unlawful handling of classified documents confirms what a former FBI special agent noted earlier this week.

“This is a nat sec/CI issue,” tweeted Asha Rangappa Tuesday morning, meaning national security and counterintelligence. Rangappa is an attorney, former FBI special agent, senior lecturer at Yale, and CNN commentator.

Also on Tuesday Rangappa tweeted: “Ask yourself: What kind of info makes its way to the WH, and specifically to the president? —> HIGH LEVEL SECRETS. PDB stuff. Defense info. These aren’t low-level diplomatic cables or overclassified State Dept. correspondence.”