Dunno why you'd kill a load of innocent animals, you'd be just as bad if not worse than the farmer!!
The best way to go about business is let the police do their investigation. Let him get his sentence. Let him do his time. Then when he's out kick the f**k out of him so he's sucking soup through a straw for the next year....that's IF he killed these dogs for no good reason.
If they were worrying stock then you wipe your mouth, move on and learn from your mistakes. Stock break the f**k out of your dogs lads and lasses