He is probably not going that far, Tinamary. I'd ask around your neighbours. Is there an elderly lady down the road who may be feeding him fresh prawns or something?
Cats are notorious for pulling this kind of stunt.
Once there was a bloke whose cat went out every morning at 7am and returned in the evening 12 hours later. Regular as clockwork. The bloke was so driven be curiousity about what his cat was up to, he stuck a small remote video camera on it's collar to unearth the mystery. It turned out puss was dissapearing through a hole in the hedge into his neighbour's garden where it curled up under a rose bush and slept - all day, everyday! Lazy
!!!