I lost a ram lamb to dogs years ago, never did find out 'who' did it, but I have a fair idea.
We had a terrible problem with a collie in the village, and it's cantankerous owner (worse than the dog

) The collie was attacking horses as they road past, it would come flying out of the garden, teeth at the ready ! It attacked my daughters horse one day, grabbed the poor horse by the hind leg, I had to beat it off with my whip, before it bit through his boot to bare flesh !! The Police were next to useless, and even had the cheek to tell me unless a human has been injured they were not interested, but did suggest that I called the Dog Warden. Turned out the dog had been reported a number of times already and was on the 'wanted list'. They told me to call them every time I saw the dog loose on the road, and they would come and pick it up. The fine's to get the dog out of the pound, soon hit the owner where it hurt - his pocket ! and the owner suddenly remembered that he could in fact SHUT his garden gate !!
The Dog Wardens were really fantastic, at handling both the dog and the very difficult owner. I would give them a call, see what they suggest ?