I am being cyber harassed via e-mail, public forums, and unwanted employer contact

I write an anonymous blog. Someone took offense to a recent offering. The person floods my e-mail in box with repetitive messages containing my real name, employer, college and threats involving recreational activities, has blanket e-mailed my employer and peers with threatening language, and has discovered my name, employer, college and other personal information that he is sharing/taunting on public forums. I have the offender's e-mail, IP and name. I am trying to determine what legal action can be taken to stop such harassment.