Help, my cat is a serial killer!

My cat Zacky is an indoor/outdoor cat, and he's forever bringing home prey
that he catches. Every week or so, I'll come home and find a bloody
lifeless bird in my living room (and the room full of feathers!) Or a
lizard. Or a mouse. Or these really weird worms that are not snails or
slugs, but look like snails without their shell. He also brings in these
really huge grasshoppers and then torture them to death, leaving large
insect carcasses throughout the house. It's like living with a feline
serial murderer! Occasionally, I'll catch him as he's bringing in his
captive still alive and as yet unharmed. So I'll give him a stern NO, take
it from his mouth, and carry it outside to release it. This kind of ****es
him off, but I'm not sure what else to do.
I really want to discourage such behavior. Any ideas?

-Garret
garret at garretswayne dot com