Trump said that he took them and he clearly lied to the FBI...
Classified or not, those documents didn't belong to him...
Think about that, he was in possession someone else property and refused to return it, then lied to the FBI he had it, FBI then arranged with Trump representatives to search for Government property, they found it... Trump still refused to help and deleted security cameras to cover him moving the property...
Let's be clear, anyone else you are fucked before we are even talking about security classifications..