House Trained Dog Peeing and Pooping in the House

We adopted a Pit from Albuquerque Humane in March 2010. We were told she was mostly an outside dog, but that she was potty trained for inside. She did very well up until 2 or 3 weeks ago. She is urinating and pooping in the house? Is there any product we can spray on the carpet for her to stop? We take her food and water away by 6pm. This has happened twice this week. Help!

By pitowner from northeastern NM