He didn't tamper with it. He just deleted it.
Remember when the Clinton administration downgraded the PBX systems in the West Wing so they couldn't trace calls to the actual extension, and then Al Gore's emails were deleted and the backups were corrupted because of a "mistake" in the coding of the directories?
I'm always amazed at how these mistakes and errors always go one way, and then nobody is punished for it.
-PJ
Either way, it’s spoliation