Someone registered on Credit Karma using my information, do I have any legal recourse?

Yesterday I went to set up an account at creditkarma.com. After I entered all of my information I was notified that all of my info had already been used to set up an account. They provided a bare bones version of the email address associated with the account and since I knew I had no accounts even close to the name provided, I sent an email telling them so. They responded by giving me the entire email address and asking me to let them know if it wasn’t mine. Turns out the email belongs to my ex-sister-in-law who had access to all of my information through my ex-husband. I have gathered all the information I can showing who holds the account (she opened a YouTube account and posted videos that pretty much confirm her identity), and now I am wondering if what she did is illegal (identity theft?) and if I have any legal recourse. I will call my attorney in the morning, but this has me super creeped out and I would appreciate any insights. Thanks!