dear dr. leelefever,

i suspect one of my friends of being a closet zombie. i've known him for quite some time and we get along just great but once in a while he would say things like "i want to eat your brain" or "you know, zombies are people too!". your zombie identification system is great for beginners but how can i be sure? i mean this is my friend we're talking about. is there are way to be absolutely sure without hurting his feelings?

lifeless in new york,
sox

ps: any tips on spotting werewolves?