But then again, can they really prove beyond a reasonable doubt that he was the one who deleted them? The forensic evidence in this case didn't seem all that well-developed, at least as of when they filed the complaint.
I'm not too familiar with how phones work, though. What I'm told is that the technology of this phone was pretty subpar; it could barely access certain sites. Who knows what data the feds will even be able to glean from it.
What if he did a mass deletion of all the images, to make room for more data on his phone, and didn't review each one, and therefore never knew he'd had any CP on there? Given that he didn't tell on himself, there could be all kinds of plausible scenarios a lawyer could bring up, for how those images got on there, and how they came to be deleted, without any crime being committed.