Five cannibals get appointed as engineers in a Oil Company. During the welcoming ceremony the boss says: "You're all part of our team now. You can earn good money here, and you can go to the cafeteria for something to eat. So don't trouble the other employees". The cannibals promise not to trouble the other employees.
Four weeks later the boss returns and says: "You're all working very hard, and I'm very satisfied with all of you. One of our cleaners has disappeared, however. Do any of you know what happened to her?" The cannibals disavow all knowledge of the missing cleaner.
After the boss has left, the leader of the cannibals says to the others: "Which of you idiots ate the cleaning lady?" A hand raises hesitantly, to which the leader of the cannibals says: "You fool! For four weeks we've been eating Team Leaders, Task Leaders and Project Managers so no one would notice anything, and you have to go and eat the cleaning lady!"