I would suggest to check your neighborhood and ask the neighbours/passers-by if they had seen the dog. You may also report this to the authorities. You also need to think about what he likes and accordingly check for specific places like a nearby park, food store, etc.
Thanks a lot for all the suggestions. They would definitely be helpful. I have also taken some high resolution pics of the dog from different angles so that if I need to print a handout or post them on the Internet, I can do so.