I'll answer that in two parts. First, Judge Dearie is emphasizing that this is a CIVIL matter, and Trump is the Movant. As such, he has the burden of proof, and he needs to put up. He made all kinds of allegations in the original Motion (which is, itself, a mess), and Dearie is just trying to establish the ground. Second, a tautology:
If the documents were planted, he has no claim to return of them. To the extent this is a Rule 41(g) motion under the
criminal rules (they mentioned it, but haven't yet proved any elements of it), it is relevant.
Fed. R. Crim. Proc. 41(g) provides:
Motion to Return Property. A person aggrieved by an unlawful search and seizure of property or by the deprivation of property may
move for the property's return. The motion must be filed in the district where the property was seized.
The court must receive evidence on any factual issue necessary to decide the motion. If it grants the motion, the court must return the property to the movant, but may impose reasonable conditions to protect access to the property and its use in later proceedings. (Emphases mine)
Again, because Trump is the Movant, he has the burden of presenting evidence. It says so explicitly in the Rule. Judge Dearie, I think, was just trying to move things along. Trump has yet to provide
any evidence on
any claim. Judge Dearie just wants to see what he is dealing with.
Even if seeing ghosts.