There is coverage suggesting an informant was involved, while the affidavit showing probable cause is not being released to the public.
There is blind speculation, unfavorable to some.
One thing not drawing major mainstream media speculation; limits to the attorney-client privilege. See, e.g., here and here. There can even be inferred a duty to inform, and effects upon license to practice if not informing should such a duty apply.
Trump had multiple lawyers in and out of his life after his favorite, Roy Cohn croaked.
Discussions could have revealed an intent to hold documents, with reasons and motives stated under a client misbelief of the extent of the privilege and its limits. To have and to hold. Having, discussed? Intent to hold into the future, discussed?
The notion of someone close to Trump informing authorities need not be close in a general sense, but close in terms of a professional representation, during the Trump term in the White House or after. James Eastman or Guiliani - unlikely.
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As a separate question, doesn't Trump have multiple living quarters? Multiple offices? Would you expect he owns a copying machine? Perhaps several? If scheming to hold power-related documents, would you believe he would be capable of thinking to hold copies at multiple locations - if the holding was intentional and not purely dilatory? The speculation alone likely would be short of probable cause to convince issuance of warrants for Trump Tower and other office or home locations, but what's your guess?
UPDATE: What upright and good motive would Trump have possibly held, to steal these documents? When considering that, are you at a loss but to conclude there was a malicious motive?
FURTHER: Wed. Aug. 17 - The magistrate who issued the search warrant and released it (and the property receipt) will hear a motion to release the affidavit showing probable cause. The hearing is set for Aug. 18.
The DOJ opposes release of the affidavit. Guardian. FOX. CNBC. Roughly the DOJ asserts the investigation will be impeded, information perhaps leading to ways and means to frustrate the investigation would be released, and potential witnesses might be chilled by disclosure of the affidavit contents. It appears a witness informed authorities where documents were at Mar a Lago. There is speculation about who might be that witness. The DOJ asserts that a redacted release would be so sparse as to have no public value, if needed redaction were imposed. Trump bellows "break-in" and other tripe.
They are not his documents. They are government property. He stole them. He delayed and obfuscated about prompt returning of government property. Some exigent need to move as the DOJ did likely was defined in the affidavit.
Usually a worry over sequestration of evidence or its destruction, witness intimidation, adverse national security disclosures publicly, to other nationals, or otherwise, would all be available, depending on circumstances, as cause to suggest exigent need.
Consider witness intimidation. Trump is a mean vindictive person, one of the worse to reach popular attention, and it alone, as possible or likely, would be cause to seize the stolen evidence.
Trump should have held no reasonable belief that stolen documents would not be retrieved by warrant, given his stalling.
Trump was accorded much more grace about the stall than any regular citizen would have been granted. He took advantage of his post-President status, and the government had to end run his stall to regain its property.
Trump has no rational grounds to object to what happened. But Trump is not a rational narcissist. He is an irrational one.
FURTHER: NBC news clarifies the motion for release of the affidavit was filed by media, not Trump's lawyers:
In a Fox News interview Monday night, Trump attorney Christina Bobb would not commit to filing a motion seeking the document’s release.
In their court filing, the news organizations seeking to have the affidavit unsealed argue that the public has a right to know the content of the probable cause that prompted the "historically significant, unprecedented execution of a search warrant in the residence of a former President."
“[N]ot since the Nixon administration had the federal government wielded its power to seize records from a former president in such a public fashion,” the filing said, arguing that “'clear and powerful interest’ in understanding these unprecedented events ‘weighs heavily in favor of unsealing’ the entire record filed with this Court,” including the affidavit.
Trump's social media ravings aside, the Trump lawyers appear hesitant to suggest release of a document the contents of which are unknown to them. Caution seems their best direction. Trump saw and held the other two released items. This one is not known to him and his lawyers. He rants. They represent.
The DOJ and the magistrate know what the affidavit says. The likelihood of the magistrate releasing the affidavit publicly, given assertions of the DOJ, seems low. The media can wait. We can wait. We know the man stole and held stuff he should never have taken, and he stalled over returning the stolen goods. He might have been on the verge of moving them from where, it appears, the government was told they were presently kept.
Finally, release publicly of the entire affidavit now, before the DOJ and investigators review the scope of the theft - and stalling refusal to return the goods - would arguably be premature. As in do the damage assessment first.
Congressional people might be effective in seeking a closed door review on a limited basis, people with suitable clearances be it staff or office holders, in a limited number, under penalty if revealing things, etc. But with leaks as prevalent as they are in DC, could such a process be trusted to assure continued confidentiality until a later, more appropriate time? People talk, even when swearing they would not.
The bottom line seems that the motion will be heard and denied. For multiple reasons denying release now makes sense. One can wonder why the DOJ did not move earlier, since it was apparent after Trump was subpoenaed that he was stalling and not complying. They waited months. Something exigent must have been perceived causing them to decide to move now as they did. Informant information may have been deemed subject to going stale, e.g., document movement if immediate action was not taken upon the information the DOJ held. It is speculative since only the DOJ and the magistrate know facts we do not know.
The law trusts them that way. Who is Trump to think he deserves a different set of laws? A man being investigated for multiple alleged misdeeds, including ginning up the Capitol occupation. A man yearning to keep a position from which voters removed him. A boundless ego with bounded talent and questionable judgment.