1. 6 months ago the National Archives launched a criminal investigation investigation into trump after retrieving 15 boxes of classified documents that he wrongfully took to Maralago.
2. A few months later they got a subpoena for more items they thought he still had.
3. Trump gave them back some more classified documents.
4. A source familiar with the documents told the feds they believed there were still even more classified documents at Maralago.
5. They got a search warrant which Garland authorized.
6. The FBI conducted the search and did indeed recover even more classified and top secret documents.
What is "shady as heck" is trump randomly taking however many total boxes of documents in the first place, bringing them to his own maralago resort, giving only some of them back, then suggesting the feds had planted them, then claiming he had declassified them.