In a slow cooker crock, stir together tomato puree, brown sugar, vinegar, garlic, onion, paprika, mustard, salt, dried red pepper and black pepper.

Add roast to crock and turn to coat with tomato sauce mixture.

Cover and cook on HIGH for 5 to 6 hours or LOW for 10 to 12 hours.

Remove roast to a cutting board. Using 2 forks, shred meat and add to serving bowl. Stir in enough sauce to desired consistency.