Cat keeps peeing

Hello Reddit. We have big problem. we have 3 cats in our house 2f 1m we recently got rid of our 4th cat who kept peeing on our couch. Since then our other cats have now started peeing on our couch and we're not sure what to do about it anymore. I've shampooed the couch and tired to get the smell out so they don't pee but they keep doing it. I'm at a loss. Any advice? How to get them to stop and how to get the smell out?