How do can i located this person/email"aus_28792879@yaho… - aus addy

The reason for this is that my bank and the police tried to find this cheat. The opportunity to buy a car from me and gave me a false cheuqe and that the Bank thought I was doing. HES-mail I send this "aus_28792879@yahoo.com Addy" plz try to help me and others who get "maybe now demolished. I have an ad on Craig's List and Facebook, and Yahoo Mail, and now ... so plz let me know whats I can do about it.
take care