Stinky Beagle Strikes Twice

I don't understand it. I have had my beagle since he was 5 weeks old. It is not like we just got him. He has been house broken for a long time but the past two days in a row he pooped in the house. I know that he is not sick and is not having accidents. So what is his deal! He is a typical dumb dog but when it comes to pooping in the house he is no dummy. Normally when I leave the house in the morning I am gone atleast an hour so when I come home he is sooo happy to see me that he meets me at the door. Well the little piglet was no where to be seen the other day and I knew something was up. If he does something wrong like get into the garbage or chew up one of the kids toys, he'll go down into the cellar where his kennel is kept. He knows that is where he will go to be punished. So anyway, I looked down cellar and sure enough he was in it. It did not take long to figure out why. So I slowly tipped toed around the cellar to be sure I did not step in anything and sure enough a pile of poop was behind the couch as if I might never know. He must of thought he was clever. So he spent half of the day in his kennel as punishment. He did not make a peep because in his own doggy way, he knew he deserved it. Well, then today he did not even wait for me to leave. I was in the kitchen and smelled something foul. Immediately I yelled,"BINGO"! He put his ears down and headed for the cellar. I followed behind, looked in the same spot as yesterdays pile but nothing. He thought that he might pull a fast one and confuse me. He left his stinky stuff in the laundry room. SO again I put the dumb dog in the kennel where he spent all morning. I am hoping that he will learn his lesson and go poop outside. I don't know what to do.