That is just too sad for both dogs!! Pits are great companion dogs, and one of my favorite breed, but unfortunately a lot of people who own one do not understand the breed and accidents like this happen! I hope they find the dog owners and they pay for it...as per the dog atacking the yorkie, let's not forget that he is a animal, doesn't know right from wrong, pits were developed to be combat dogs, to kill other animals, so it is only in his instinct, that is why not everybody should have one!
I hope the little yorkie survives..