you mentioned that you saw a little purple. was this in the form of blood, or particles of some kind. this may be a part of the liver. if it is stomach contents, are there beets, or turnips in the area the buck may have been feeding on? cover all the bases first. since you are waiting til morning, if the deer is gut shot or shot in the liver with a little luck you will find the animal. it should get cool enough tonight that the meat wont ruin, unless it is gutshot. good luck. i know it is a sickening feeling to loose an animal.