SPCA chief Roy Gross said the incident occurred sometime in the afternoon on the Pilgrim Psychiatric Center property.
Joey was taken to West Islip Emergency Veterinary Clinic by Islip Animal Shelter personnel.
According to veterinarians who treated Joey, he suffered from multiple neck fractures, was malnourished and had bite marks on his neck.
The wounds indicate that the puppy was probably used as a bait dog by dog fighters.
Joey's story has sparked so much outrage nationwide that the reward is now one of the highest ever for a case of animal abuse.
Anyone with information is asked to call the Suffolk County SPCA at 631-382-7722. All calls will be kept confidential.
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