Bicycle detail

I was on my front porch with my bike and gear waiting for a friend to pick me up for a mountain biking trip in Michigan. I stepped inside to make coffee. I heard the porch door open and slam shut. I stepped back outside and the bike was gone. I went to the sidewalk and saw a male under 35 years old with dark complexion between 5'6" and 5'10" wearing a white shirt riding away with my bike. I chased on foot northbound on Stevens Ave until this person turned West on 35th Street and I could no longer keep up.