How to trace the person who send email messages

How to trace the person who send email messages:

The easiest way:

The facebook have the details of the more than the billion users in its database unlike the some other social networks facebook will offer the offer that in the search to find the email address are exists In its database or not to view the data.

The traditional way:

Open the email header and view the received from the ip address in the brackets copy the ip address and with the use of the online trace root tool we can find the approximate location of the anonymous user.                              

                                                                                       Or

Use the knowem to find the email address with particular username is found in any social networks.

Modern way:

Use the spokeo online tool to reverse the email lookups.