Can we attack a zombie?

As evidenced by this story sometimes a prank can go horribly wrong. But suppose a real zombie shows up on your doorstep, moaning for brains and smelling so foul you almost regurgitate your lunch on the spot. Do you risk further investigation and ask yourself if this is really a zombie or some punk kid trying to scare you? Now suppose you don't take any chances and cleave that zombie's skull nearly in half with the machete that's always within reach for such an occasion. When the dust settles and you have a "dead" corpse on your porch, close examination proves beyond a doubt that you were in fact dealing with the undead. What's the next step? Maybe the authorities won't believe you if you claim a zombie attacked...maybe they just charge you with manslaughter despite the obvious state of decay. Instead of being honest, you might be better off making up a story about a raving lunatic beating on your door and saying he wants to kill you. Or maybe it's time to start that concrete porch in the backyard....now where's that shovel...