Dealing with a real Death Note

[robvalue]

This is an imaginary fantastical scenario question. For those not interested, please drive through!

For those not familiar, Death Note is a brilliant manga/anime series about a titular magic book, which has the power to kill anyone whose name is written in it. (There's a bit more to it, but I won't spoil it for those who haven't seen the show yet.)

Pretend this happened for real; or at least, it appeared to. A series of unexplained deaths all happened to be recorded in a book this guy had. Further observation of the guy shows that people continue to inexplicably die shortly after he writes more names (minimum 40 seconds in the show).

What would be the legal implications? If there was no physical evidence that connected him to the murders other than writing their name, could he be held accountable? Would anyone even have grounds to confiscate the book? Would the law eventually have to change, or special consideration be made, assuming he just continued to "kill" people?