The FBI believed there was probable cause that highly sensitive documents that contained US national defense information were scattered across Donald Trump's resort in Florida, according to a partially redacted affidavit used to justify the search of the property unsealed on Friday.
The affidavit - extensively redacted by the justice department to protect details about the criminal investigation into Trump's unauthorized retention of government secrets - also provided additional new details about the materials he had retained at Mar-a-Lago.
According to the redacted affidavit, the FBI sought to retrieve national defense information across several rooms at Trump's resort, including his residence, the foyer to his residence known as Pine Hall, his office, as well as a storage area, among other locations.
The exact basis for the FBI's suspicion was not clear, and vast passages of the affidavit that appeared to indicate how the justice department had that knowledge were blocked out in order not to reveal the "roadmap" of an investigation that remains in early stages, officials said.
The document said that justice department leaned that a preliminary review of 15 boxes taken to Mar-a-Lago "indicated that they contained 'newspapers, magazines, printed news articles, photos, miscellaneous print-outs, notes, presidential correspondence, personal and post-presidential records, and 'a lot of classified records'.
"Of most significant concern was that highly classified records were unfoldered, intermixed with other records, and otherwise unproperly [sic] identified," it warned.
The order to unseal the document came from judge Bruce Reinhart, who approved the warrant and is overseeing the case from West Palm Beach, Florida. It instructed the justice department to submit the redacted affidavit that he had reviewed in the public docket before noon leading to a tense, breathless wait for many observers in the political and media world.
In an earlier two-page ruling, the judge said the justice department's proposed redactions were narrowly tailored to keep secret grand jury material, the identities of uncharged individuals and sources and methods used in the criminal investigation - and the remainder could become public.
"The government has met its burden of showing that its proposed redactions are narrowly tailored to serve the government's legitimate interest in the integrity of the ongoing investigation and are the least onerous alternative to sealing the entire Affidavit," Reinhart wrote.
The affidavit contains key information - notably the probable cause - about the justice department's investigation into the unauthorized retention of government secrets at Mar-a-Lago, which, according to the warrant, could constitute violations of at least three criminal statutes.
The imminent partial release of the affidavit is set to prove a major juncture in the developing investigation, being led by the justice department's national security division, and the attorney general, Merrick Garland, who personally approved the warrant after days of deliberations.
Exactly how much of the affidavit will be redacted was not clear, but they are expected to be extensive. The justice department had originally opposed unsealing the affidavit at all, and only filed a redacted version after being forced by Reinhart last week.
But depending on how the affidavit was produced, several former US attorneys said, it could also contain elements that are not directly related to the investigation, such as descriptions of potential crimes that the justice department suspected were being committed at Mar-a-Lago.
The former president has indicated on his social media website that he supports unsealing the affidavit but his lawyers never filed a formal motion to that effect, and instead left the effort to a coalition of media outlets that pushed to have the affidavit become public.
Trump has since filed a separate motion to have a so-called special master appointed to determine what seized materials prosecutors can use as evidence in the investigation, and to force the justice department to provide a more detailed list of what was retrieved by the FBI.