The FBI knew exactly what it was looking for at Mar-a-Lago, and went straight to it when agents descended on Trump’s “Winter Palace” (see the real, and grander, Winter Palace here). That’s prompted widespread speculation — and assumptions — there’s a snitch in the tsar’s inner circle (see, e.g., story here).
Not one to miss an opportunity to get in pokes at Trump, his convicted (and unpardoned) former personal attorney, Michael Cohen, suggested it might be Melania (see story here, and ignore loud snickering in background). I doubt it; she’s far too loyal to him (why? — ed.). A Guardian story (here) suggested it might be Ivanka and/or Jared (noting how they’re working against him in other ways, not least Ivanka’s refusal to endorse his election lies).
But another Guardian correspondent on an MSNBC show offered a more pedestrian theory: There isn’t one. He said “a lot of this has come from the Trump lawyers themselves,” adding that “the Justice Department grew concerned about that classified material at Mar-a-Lago as a result of interactions with the Trump’s lawyers” (see story here).
This is plausible. It’s known that Trump’s team was in negotiations with the Justice Department over the materials he took with him to Mar-a-Lago, which apparently broke off in June without the materials being handed over, and it seems likely those conversations got specific about what was there, and where and how it was secured. And at some point, with the attorney general’s approval, the government decided to go get it.