Dog is peeing/pooping in the house

Question
y dog would run off all the time, so my friend suggested that I get him neutered, which I did. Now he poops and pees in the house once a day. He is outside for most of the day while my finace and I work, but as soon as we bring him in, he runs downstairs and goes to the bathroom in the same stop. He knows he is not allowed, because when we walk down stairs, he runs into the other room with his tail between his legs. I think he is doing it out of spite. we are at our whits end. Please help us!

Beth

Answer
There are some questions I don't have a good answer to, but will try.  It could be he mostly sleeps all day while you are gone.  Then the burst of activity when you return stimulates elimination.  Try stimulating him outside before bringing him in, some fetch or even a walk.  Once he voids himself outside, then you can go in.