Do you think this was cruel of my mum?

She ran over the neighbours cat, and it was still alive but she didn't want to get in trouble for it. She looked if anyone was round, then she grabbed it by the tail and threw it over the neighbours bungalow. She parked the car and ran over saying to the neighbour that a hawk dropped the cat. And she offered the neighbour a lift to the vets but the cat was dead. What should I do?