Answers:
I've answered this form of examine back. Just judgment the email's header, which displays the IP address of the sender. If the character you are looking for have a static IP address, or if his/her ISP's caring and cooperative adequate to provide you their DHCP logs, you can establish that a faddy human being sent the email.
actually you can't,especially if it is net base e-mail, similar to google or yahoo etc.
But even contained by a POP3 story, approaching one you find from your ISP is difficult to do it.
You can click on an e-mail, choose properties and found the server from where on earth the e-mail convey but zilch more.
Well if this e-mail is the POP3 report ISP supply to a client afterwards from server you can find the country too. But that's it.
Now single surrounded by cases a crime commited, you can shift to local authorities, sue this individual, local authorities if they're sure contact the FBI, and FBI telephone call an auitorney who may ask the clients term from the ISP.
So as you see like mad empire involved and they won't do it for nought.
Privacy thorny to break, even when you're online.
Ofcource if you want it by the decree.
There are some things you can try ,but that's improper and not subject for this thread.
Good Luck