Its vital that whoever did this is found. Setting the dog aside for moment (a truely awful act), people who engage in this type of activity graduate to doing similar things to people. Think about it. I doubt that skinning a dog alive was the first act of insanity this person has done. If not found and dealt with, eventually someone will be tortured, mutilated and/or killed.
Frozen One: I was going to say the same thing, but read through the posts, to see if someone else said it first. This is how most seriel killers, and just plain bad people get their start.