Someone is pretending to be my husband

My husband has a non-expiring restraining order against his ex girlfriend.

He recently pressed charges against her for signing him up on the dating app and impersonating him on “The League”. We have ongoing litigation issues so I don’t want to give too many details.

Is there any way to find out if he was signed up for any other dating apps? Everything that I have searched for costs money and feels like a scam.