Open source intelligence investigation of Email

As intelligence analysts, we may use Email addresses to gather personal information for intelligence investigations.

People tend to leave their business Email addresses for business purposes, but didn't know that would go a long way in uncovering the trove of private information in the open source intelligence investigation.

Here is an Email open source intelligence investigation flow chart, including investigations from the name of the mailbox, related domain names, numbers, etc., which can make Email's open source intelligence investigation way clearer.