I have heard the following dialogue in the TV series "La Mante":
- Comissaire Ferracci: Dans votre lettre, vous disiez que vous aviez le pouvoir de m'aider
- Jeanne: Vous en êtes où?
- Comissaire Ferracci: Je ne peux rien vous dire.
Context: Jeanne Deber is a serial killer who was arrested by Ferracci and has been locked up in a prison for 25 years. After a copycat starts to replicate her murders, she sends a letter to Ferraci offering her help. They say the above lines when they meet.
I have read in https://www.linternaute.fr/dictionnaire/fr/definition/en-etre/ that "en être" means "to participate in something", but I'm not sure how it fits in the above dialogue. What is the difference between "vous êtes où" and "vous en êtes où" in this context?