I think O'Donnell misinterpreted this. When the IT Director said he didn't "have the rights" to delete the files, most likely he meant his login account didn't have Delete privileges. That's why they sought out the Security supervisor, to find out if he did.
My guess is no one present had the privileges. Rather than expand the conspiracy, they called Trump and decided to call it off.
@WordsmithFL This was exactly my interpretation. It wasn't a matter of right and wrong, it was a matter of not physically being able to do it. My guess is that person 4 would have been willing to do it because he was pulled aside and asked privately. They may have known that anyone who could do it would never do it because they know what is being asked and who would be going to jail, so they dropped it.
@WordsmithFL Someone did have access and permission to delete that server and they were not asked. At least according to what we know thus far.
@WanderingDabbit I agree. It probably would have been a regular technician, maybe even a contract vendor, who wouldn't cover for Trump. That's why they decided to drop it.