Need Help to find the ip

[Ineedhelp]

Hello,

Got a big Problem. My best friend and Her Partner got a weird Letter with lies about her and so on. There was No Sender. We thought It was over after the Letter but now they got a Mail and this Case goes on. We cant go to the Police because there was No threat against both, but she is in fear now. I only have the Email Adress and We are thinking the Mailaccount is deleted also. Is there a Chance to get the ip or at least to know where the Account was created.

[Chrispcritters]

When you mean, "they got a letter", do you mean a physical letter or an email?