Dog Pees and Poops Inside When Left Alone?

I have a mutt that is 5 years old. We rescued him from the pound when he was one. When we leave, he poops and sometimes pees in the house. Even if we take him out right before we leave, then forgot something and 1 minute later go back inside he is in the act of pooping, like he is doing it on purpose. He is a great dog! Only when we are gone does he act up. We tired the crate and he not only chewed through one cage but three cages. One was metal and the other two were a thick plastic. What do I need to do?

By Krystal