A new article at the Atlas Obscura details the adventures of an unusual historical heroine:

Impressed by her faculties of logic, resourcefulness and quick wit, Houdini invited Rose to join the team of about 20 salaried undercover investigators that he referred to as “my own secret service.” This clandestine team traveled ahead of Houdini’s touring schedule, visiting towns and cities where he was due to perform and infiltrating the local Spiritualist “scene” to gather evidence of fraud. These details were passed on to Houdini, who would then expose the fraudsters during his shows.