De-anonymization of Email Owner
There are several ways in which law enforcement agencies or hackers establish the identity of an email owner. Typically, this occurs through obtaining the IP address, which is then used to determine the identity of the owner. We described how identity is established through an IP address here.
The IP address is not the only tool for identifying the email owner; modern email services often have information about the user's phone and payment data – all of this can lead to de-anonymization, as can the content of the email inbox, which, when analyzed, can accurately point to the owner.
Official Request
Many believe that the ability to send an official request and obtain data is only available to law enforcement and intelligence agency employees; however, this is a misconception. Fraudsters often skillfully disguise their requests as those from law enforcement, forge court decisions, and obtain data about victims. I have encountered such cases. "Drawing up" a court decision in the darknet is not expensive, and not every email service owner knows how to verify its authenticity.
This trick is unlikely to work with giants like Google or Protonmail, but it is still worth keeping this in mind. The recommendation in this case is simple – use trusted email services that have a qualified legal department.