The 31-year-old woman observed three men attempting to steal the catalytic converter from a vehicle just before 5:45 a.m. Tuesday.
The men then approached the off-duty officer's vehicle.
She began recording the suspects when they came over. Two of them reached into their waistbands in what she said was an intimidating manner.
She pulled her weapon and fired one round from her car. It's unclear if any of the men were hit.
The three suspects fled in a dark colored BMV.
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