Bicycle detail

My brother and I were unpacking our car to take a ride down the Riverwalk. The bike was resting against a barrier not even four paces away from us. Two people road up on a bike (one pedaling and one on the handle bars). The one on the handlebars hopped off and was gone with my bike before we could even react. We gave chase and caught the one without my bike, but he was let go after we received gun threats. Police later arrived and took down a report from us.