Intercepted

I recently intercepted this letter from a grade 10 student.  Note: The grammatical structure, punctuation and spelling has not been altered.

Dear Chris, your pencil case has been taken hostage. Because of the careless way of treating him, your pencil case is now at my mercy. I've beaten him and starved him for weeks. If you ever want to see you pencil case alive, you have to meet my demands. In exchange for your pencil case, you must provide me with the funniest joke in the world, if it doesn't make me laugh, your pencil case is dead. You better hope I'm in a good mood. Bring me the joke ASAP after you receive this ransom. Love: the mysterious and inidentifiable killer 

And the joke: Chuck Norris can whistle in 5 different languages - including sign language.  Needless to say, the pencil case was saved.