Have you ever taken a pet to a shelter? Why? Could you follow up on your ex-pet? How'd you feel?
That is horrible when the idiot that was trying to kill them failed. Back on the farm years ago they use to drown animals before winter, as it was more humane than letting them live in the -50c weather. There was no room for barn cats and such. But on the farm... they made sure to do it right the first time. What you found is just cruel....and I spotted a plastic bag moving by the water and Diesel ran to it and looked back at me so I went and opened it, there were 6 kittens in the bag! All but two were dead