Bike Thief in neighborhood

This morning at around 9 a.m. I found a man trying to take a bike off of our back deck. I told him to stop and he left the yard and ran down the alley toward Randolph. Just letting you know that there is someone in the neighborhood. He was an African American, dark complexion, average build, not real tall, between 5'8" and 5'10" wearing a dark colored baseball cap, wearing a dark t-shirt, but carrying a white one. Police were notified.