Hillside Oaks

I cannot find my chihuahua!!! He was in the back yard (12/18). I had him on his leash so he could go potty and sun a bit. Somehow, he got loose and took off down the back alley. We have looked and looked and looked and now I am beginning to think that someone took him not long after his escape. He is a Blue Chihuahua, deer, no more than 3lbs, light grey. He had his leash still attached to his collar, which also had vet tag and personal tag. Did you see anything???? Does your neighbor have a new pet?