he knows he's not supposed to do it,but he still does it!
It sounds to me like it has become a game for him. Malone has a wicked nawtee streak in him, and I have learned that bad behaviours {such as ripping magazines} need to be caught in the act. Malone was not allowed to roam around the house unsupervised, so that when he does nawtee things, I could catch him in the act.

To discipline him, I would put him in a settle position (on his side, with me over top of him) or he would get a time-out in his crate. It didn't take him long to figure out that acting nawtee was serious business.