Surveillance video shows a person run into Maaz Jewelers at Tanforan Mall, and take a crow bar to the display case.
Watch, as owner Usman Bhatti confronts the thief, then draws his gun, which he's licensed to carry.
The thief and two others standing outside the store ran off, empty handed.
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Bhatti says lawmakers need to act to protect businesses like his.
"Do something, anything, it's their job to protect us, to make some sort of law, we can protect ourselves at least," he said.
Bhatti says unless something changes, business owners like him will remain on their own.
He doesn't blame police, saying they can't be everywhere, and couldn't possibly respond fast enough to stop crimes like this.