Not coming home

My cat 8-year old cat Oscar is not coming home. he has been gone for 2 weeks. We just now found out where he is... he lives at another persons house. What should i do?

Do the people that Oscar is living with know that he already had a home? They may have just thought he was a stray and took him in. I'd go talk to the people that he is currently living with and tell them that you miss your cat! It was probably just a misunderstanding.

I agree with cg33: you need to approach them (diplomatically), "assume" they didn't know Oscar belongs to you.
Is he microchipped? You may need proof (pictures?) he is yours.

You've gotten excellent advice and I don't have anything more to add.   There are people in this world who see a cat outside and just assume that the cat is theirs for the taking.  I have personally known people who are like this, and they don't make even the slightest effort to find out if a cat already has an owner.  Good luck getting Oscar back and let us know what happens.

My feeling is that if a cat shows up at my house and nobody posts a cat missing sign, then they don't care enough about getting him back.  If a sign was posted, I would most certainly call them. I have done so on several occasions even when I SAW a cat that looked like theirs.  If your cat was at my house and you had not posted a sign, I would assume someone had moved off and left him as it happens very frequently here.  Fortunately, lots of people here like cats so they always seem to find someone to feed. them.

I do have one of my neighbor's cats here and he knows it.  The cat keeps coming back.  They have 3 dogs now and put in a dog door which the cat can use whenever he wants.  He can come in and eat, then go out again.  They have two other cats that don't come over here, at least not to hang out, but that one does.  He lies around in the fenced yard with my cats.  I do not have dogs and do not have a cat door, but the cat will come running inside every chance he gets.  Once my neighbor was satisfied that his cat was safe and was just making a choice, he has become resigned to it.  At first I used to take the cat back over there, but it's like the song "The cat came back!"  The neighbor is next door, our houses are not close together -- we each have an acre and we're each in about the middle of our lot.  He's up on a hill and I'm down in the hollow.  We've just agreed to share the cat, he can eat there or here, we feed the same food.  I think the cat gets more attention here, he's a love hog.