Gray tabby cat with blue collar and white paws

I lost Milo, my gray tabby cat with white paws, yesterday around 3pm. He has a blue collar with a tiny silver bell and a small white heart-shaped patch on his chest. He's medium-built and a bit skittish, but he loves tuna and will come running if he hears a familiar whistle. I last saw him around the Court Square fountain on Main Street in Harrisonburg, but he could have headed toward West Market Street or slipped into the alley behind the Coffee Break cafe. This cat means a lot to me; he's a rescue and was a gift from a friend, and I really need him back.