Firstly,
have you given your email out to anyone else on the site as they could have passed it on
he sends death pictures???? jesus this guy must be demented or something, i'm sure if these pictures are serious enough something should be done by hotmail, maybe send them an email asking for help because that's sick
and in terms of tapping into your pc
could be anything
do you have a firewall installed?
he could just be hacking into your ports ont he computer
i don't really know much about hacking but almost anything is possible these days
hope you get it sorted :)