I'd say the victim was a criminal to the point that he was trespassing on private property, but my concern is that everything beyond that point is based on the assumption of what he was doing, not the investigation of it.
Thing is, a few weeks ago when coming home late with Sharon, I noticed a mobile phone in someone's front garden. I went into the garden, picked up the phone, took it to their front door and knocked to ask if anyone had lost a phone (asking its make to ensure accuracy). This is not an uncommon occurrence in areas of Europe. I'm not saying that this young man definitely had no criminal intentions when he entered the property, but there's no assurance that he did have criminal intentions either.
What concerns me more is the idea of sitting up all night with sensors, gun at the ready, while you try to deliberately lure in criminals to shoot. That's not really an indication of a healthy attitude towards home-safety and more an eagerness to 'shoot me some baddies'.