Making a Death Note?

In short, I'm looking for help to create a Death Note in Minecraft. I've no idea if this is even impossible, so all ideas are welcome.

I have three key requirements for the Death Note:

1. Item has to be a written book or a book-and-quill.

2. It is possible to kill any players or named mobs of the user's choice, by writing in the book or clicking on prewritten text.

3. You can use it whether or not you have operator* status.
   (I'm fine with a command chain that /op the player, execute a command from their client, and instantly /deop them)

It'd also be a cool bonus if the user can designate the time or cause of death, but that's not 100% necessary for my idea.