Forget the 22's, rat traps, etc. Who has time to try to stalk a squirell in the attic, or have your wife have a canary if you get him in a rat trap and have to finish him. Go to your local sporting goods store, and buy yourself a #110 Conibear trap, dab peanut butter on the prongs and leave it up in the attic, it won't take long, and you won't have to worry about finishing him off.