You cannot find out who it was. It could have been some random user who entered the wrong user ID. But if you are worried that someone is trying to get into your account, change your password.
https://ttlc.intuit.com/community/account-updates/help/how-do-i-update-my-turbotax-account-informati...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
