Theft Description

In the brooke, some guy with golden puffer jacket, looks old and out of school, I was walking with a friend down the brooke, I let my friend ride my bike in exchange for their phone (friend wanted to ride it, it was his responsibility now), he crashed into some guy (mentioned above), the guy asked to have my bike (which my friennd was riding) and with no hesitation my "FRIEND" just gave it away, I couldnt do anything. I chased after the guy but he had the bike and I couldnt run very far, "FRIEND" just laughed. Please HELP