If he *did* cap the dog, it would make me very happy and I'd congratulate him. But, in terms of aggravation and paperwork, he'd be better off calling animal control and *telling* them he's just about mad enough to shoot a habitual stray. That tends to motivate the dog non-catchers. If that doesn't work, he should call the cops and repeat the threat. They cannot bother you for simply saying you're going to do it. But, they may be personally acquainted with the dog non-cathcer and be able to better motivate him to get off his fat ass and enforce the dog laws.