If the dummy account has a unique username in the URL, type it into a search engine.
Tracing a "dummy" or fake Facebook account is difficult for regular users because Facebook does not share private registration data like IP addresses or email addresses due to privacy policies. While you cannot directly "trace" an owner through the app, you can use investigative techniques to gather clues or report the account for removal. How to Investigate a Dummy Account how to trace dummy account in facebook