I would be careful what you do concerning the loaded paint brush....
You would have to show he/they forced their way into your home and in an act of self defense..(say he threatened you with wallpaper)..you defended yourself with the brush. I would suggest that if you painted him and then called the police....make sure to swipe the brush against the wall or ceiling nearby to prove you gave him a warning shot.
Also, make sure they are fully inside your home. If you painted him half in half out the door...drag the body in but be careful not to smear the paint across the floor..it'll give you away..