>>5910647 lb
This raid might have been even legal.
If something had been "found" during this raid and would be important enough to prosecute, then this evidence would be needed to present before court, I assume.
You have something obtained, but you cannot use it before court (for whatever legal reasons).
But when the FBI or the police raids an office and coincidentally becomes aware of material that is evidence for an important crime…they would have to bring it before court…and then you have your evidence, where you wanted it to end: at court.