Before the events of Murdered: Soul Suspect, she was Iris's twin sister. They were also both Mediums, people who have the ability to see the world of Dusk, making them a target to the Bell Killer. When the killer kidnapped the pair, Rose saved Iris but was caught and taken by the killer to be burned at the stake, one of the many execution methods used during the Puritan era Salem Witch Trials.
Murdered: Soul Suspect
During the events of the game, Rose is a ghost inhabiting Dusk. She has possessed her sister, Iris, for some time now in order to get her to the Mental Asylum to keep her safe from the Bell Killer. She is first encountered in the investigation "Iris's Room" when she leaves Iris's body after Ronan and Joy conclude their investigation. The four leave shortly after, with Ronan traveling to the Museum Exhibit and Rose, Iris, and Joy traveling to St. Benedict's Church.
Her sister is later killed, crushed by a falling statue. With the two of them reunited in Dusk, they ascend to the afterlife.