As I've said before on here, according to the RSPCA, 95% of prosecutions for animal cruelty are brought against animal owners.
The case of the dog in Bootle reminds me of my uncle who used to be a bus guard in Manchester when some buses had doors at the near side rear. A guy with a dog jumped on the moving bus and the doors closed before the dog could get on. The bus sped away for two stops without the driver knowing and when he stopped, the dog dropped dead. Just an accident. Cest la vie.