Your first option is to call the local animal control beureu. They vary by state in terms of what they'll do. When I lived in New Jersey, animal control wouldn't do anything unless the animal was some sort of threat.

The antifreeze thing...it's bad but not as you all might think. Antifreeze actually has a 'sweet' taste to it and can be palatable when mixed with other things. Antifreeze is not known to metabolize in organic bodies. Instead, it kind of collects, slowly poisoning the organs around it and sending the organism into septic shock. This is to say that you shouldn't notice a rash of dead cats in your hood tomorrow. Over time though, they will eventually fall ill and die.

Definately report the person to the local animal control. Poisoning domesticated animals is not needed.