Can she be held criminally accountable for holding back evidence or tampering with the cell phone ?
Withholding evidence is more likely to be subject of a civil lawsuit. Lower standard of proof (preponderance of evidence vs. beyond a reasonable doubt).
If she was actually the one who tampered with the cell phone, then she could be prosecuted for that. I would look at evidence but I would never personally touch it. That’s for the cops and forensics people.
If she actually “played with” evidence outside the courtroom, she is, again, dumber than I thought.
The Courtroom was my playground, trials were play time, and the evidence was my toys. That was when you get to take out the toys and play with them. And you do it out in the open where everyone can see. That’s the whole point of playing.