The police interview

A guy walks into a police department. What can I do for you? Asks the police officer on duty. I'd like to join the police department, he says. Amused and bored, the officer decides to interview him and ask a few questions. What's 2+2? He says 4, what's the square root of 100? He says 10. Good, now who killed Abraham Lincoln? Puzzled, he responds hmmm, I don't know, the officer smiles and tells him to go home and think about it. The guy goes home and calls one of his friends, who asked him if he got the job. He responds excitedly, Not only did I get the job, I'm already working on my first murder case.