Four ewes are believed to have been fatally shot and four other sheep have died following what appears to be a dog attack in the Coelbren area.
Dyfed Powys Police is appealing to anyone who has more information to help with the investigation into this incident. A picture issued by police shows the bloody wool surrounding the wound of one of the sheep involved.
Responding to the incident, NFU Cymru's Rob Lewis said: “While the vast majority of dog owners believe that their dog is docile and would not harm sheep or other animals, dogs can cause distress, injury and death to livestock if they are not walked responsibly, particularly when that dog is not familiar with livestock.