Facebook is the most awful abusive place.
What they did to that dog is appalling,horrific,a crime,can you not phone the police and get this investigated?It may help things to know these lads are arrested and charged and stopped from doing it again.I'd have to try find them and bring them to justice.Not that there is any blame on you if you are unable to achieve this.I feel the pain and horror that you do,my heart breaks and I feel down now too.
I love animals with all my heart and can't stand to see or hear that they have been hurt.Makes me angry and so sad too.