Who killed Abraham Lincoln?

A blonde walks into the police department looking for a job. The
officer wants to ask her a few questions. Officer: What's 2+2? Blonde: Ummmmm... 4! Officer: What's the square root of 100? Blonde: Ummmm... 10! Officer: Good! Now, who killed Abraham Lincoln?
Blonde: Ummmm... I dont know. Officer: Well, you can go home and think about it.
Come back tomorrow. The blonde goes home and calls up one of her friends, who asks her if she got the job. The blonde says, excitedly, "Not only did I get the job, I'm already working on a murder case! "