The FBI raided former President Donald Trump's Mar-a-Lago resort on Monday.
The raid came after the Department of Justice subpoenaed classified documents.
The Washington Post reported that some of those documents related to nuclear weapons.
The search of former President Donald Trump's Mar-a-Lago resort and home in Florida has set off a firestorm, with his allies condemning a rush to judgment even as they claim the Republican leader is a victim of political repression.
In the meantime, sources familiar with the investigation say the FBI - led by Trump appointee Christopher Wray - was searching for top-secret documents related to nuclear weapons.
Here's what we know so far about Monday's raid and the events leading up to it:
National Archives said Trump had classified documents
Back in February, the National Archives, which is charged with the safekeeping of presidential records, asked the Department of Justice to launch a criminal investigation after it said staff had collected 15 boxes of documents, including "classified national security information," that were improperly taken from the White House to Mar-a-Lago following Trump's term in office.
At the time, Trump described the return of the documents as part of a "collaborative and respectful" process, saying it was a "great honor" to work with the National Archives.
Investigators obtained subpoenas before the search warrant
In the months following the National Archives' request, federal agents asked Trump's staff to better secure the basement room at Mar-a-Lago where they believed presidential records were being kept, specifically requesting that a padlock be added to the door.
At the same time, investigators obtained a subpoena from a grand jury for documents they alleged were still wrongly in the former president's possession. In June, Jay Bratt, chief of the counterintelligence and export control at the Department of Justice - now armed with this subpoena - came to Mar-a-Lago, obtaining from Trump's attorneys at least some records that were marked as "classified," CNN reported.
Weeks later, the Trump Organization was handed a subpoena for surveillance footage from Mar-a-Lago, which it reportedly handed over.
Mar-a-Lago informant alleged documents were withheld
According to The Wall Street Journal, following that June meeting, "someone familiar with the stored papers told investigators there may be still more classified documents at the private club." That source potentially laid out the case investigators used to have a judge sign off on a search warrant for Mar-a-Lago that was executed on Aug. 8.
Merrick Garland authorized the search
Citing the publicity around the case, Attorney General Merrick Garland held a Thursday evening conference where he confirmed that he approved of the search.
"First, I personally approved the decision to seek a search warrant in this matter," Garland said. "Second, the department does not take such a decision lightly. Where possible, it is standard practice to seek less intrusive means as an alternative to a search, and to narrowly scope any search that is undertaken."
Garland also announced that the Department of Justice was moving to unseal the search warrant itself, as well as the inventory of goods taken from Mar-a-Lago. Trump has claimed he supports releasing that information but has not done so himself.
In keeping with department policy, Garland did not comment on the nature of the investigation.
Hours after Garland's press conference, The Washington Post reported that classified documents "relating to nuclear weapons" were among the items the Department of Justice sought at Mar-a-Lago. It is unclear whether the documents related to US weapons programs or the capabilities of other nations, the paper reported.
Search warrant reveals Espionage Act investigation
On Friday, The Wall Street Journal reported that 11 sets of classified information, "including some marked as top secret and meant to be only available in special government facilities," were recovered from Mar-a-Lago, citing a receipt of items taken on Monday.
The receipt also included documents pertaining to the pardon of Trump ally Roger Stone and information concerning the president of France.
A copy of the search warrant, obtained by multiple news organizations Friday afternoon and later unsealed by a federal judge, revealed that Trump is under investigation for three possible criminal offenses, including an alleged violation of the Espionage Act for improperly possessing documents that could harm national security.
According to the receipt, additional items taken from Trump's property include:
"Miscellaneous Top Secret Documents"
"Binder of photos"
"Leatherbound box of documents," including within "various classified/TS/SCI documents," referring to top-secret national security items
and "Miscellaneous Secret Documents"