Hannah Gruen is Nancy's housekeeper. Nancy's father hired her after Nancy's mother died so that Nancy would have a mother figure growing up.
Hannah is available to talk to in Message in a Haunted Mansion. Her voicemail can also be heard in Danger on Deception Island, The Secret of Shadow Ranch and Curse of Blackmoor Manor, but Nancy cannot talk to her in those games.
In Stay Tuned for Danger, Hannah sends Nancy a videotape of an interview with Rick Arlen that can help her on her case. In Alibi in Ashes, while away from home, Hannah sends Nancy a package of snacks upon hearing she is in jail.