Why, didn't you see the thread on Amy Winehouse? People of all ages will do things they know full well will bring negative attention for the simple reason they want attention so bad. Kids don't normally have the same ability to logically think things through that adults do so it is hard to hold them to the same standards.
From what you've said on here, plus from my own experience, this sounds like the problem is due to either a poorly thought out attempt for attention, sibling rivalry, or a combination of both. Since you've already tried punishment to cure it and that hasn't worked, any suggestion of a new form of punishment isn't going to help either. What you need to do is to find out what has triggered it.
You said that this problem has been going on for a couple of months now, so I have to ask if it ever happened before that? If not, than you can probably figure that something or someone triggered this back around that time. That's quite a long time ago in a kid's world so for him, he might not even remember the actual event, or he may not want to tell you. You, the wife, and the other adults in his life are going to have to put your heads together to try to figure out what was going on just prior to this. It might be something that an adult would think was trivial, but to a kid it might not have been.
How long has it been since you've had the kids? Did his brother get some different or special treatment for reason back then? When are the boys' birthdays? Did they have a visitation with their Mom or Dad back about that time?
Regardless of what you find, it is obvious that trying to punish him for this type of behavior isn't working, so you are going to have to try a completely new tract to break this habit he has. I think both Nate and Slonezp gave you some good advice, and those things might be worth trying. I don't think it's time to shave his head to look for the "666" birthmark yet, but I'm glad you're trying to figure out how to stop the problem before it escalates.
Good Luck