it depends on local jurisdiction, with the dog. check yours. plus, the bitten thief will sue you for 67k dollars for his pain and suffering.
build a chain-link, covered enclosure. just make it loud and risky to rip you. motion lights (facing out from flowering plants), noise emitting alarms, etc. I've found that a rep as a murderous psychopath, doesn't hurt matters. I know a fella locked a thief in a dog kennel, sans dogs, for 2 1/2 days. the thief had access to a hose, twice a day, was fed enough, and my comparde had a pig roast/keg. the thief wasn't allowed pork or beer. a sign read, "please don't feed the thief." the thief threatened charges on my friend, sure, but my friend explained some of the down-side of that, an' nothin' more was heard of thief. he left the area shortly after.
true story