Search person by email

Hello!

Trouble came to the house - the fraudsters committed a theft on a fairly large amount offline, but they first contacted, including by e-mail (sent contracts, depicting the legitimacy of the transaction). Tell me if there are any technical search tools (official and not) and if so, what is my procedure? The police told the IP address information “so we’ve already recorded the address St. Petersburg, street ...” ...

Can Mail.ru provide any information besides ip address? In particular, a person periodically appears on the project “My World”, possibly using other services. If he has several accounts, is it somehow possible to track? How do I understand requests to Mail.ru should already go from the Ministry of Interior?
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I would be grateful for any help and advice. I am aware that the topic is “unformat,” but I hope for understanding ...