Most people know that Harry Houdini was a famous magician. Many people also know that Houdini devoted much of his life to debunking fake mediums during a time when Spiritualism had widespread acceptance.

But did you know that Houdini’s chief investigator was a woman named Rosa Mackenberg? I did not, but thanks to a Skeptoid podcast episode I do now!

Mackenberg began her career working as a private detective at a detective agency in New York. She was introduced to Houdini, who asked her to help expose fake mediums. Mackenberg believed that it was possible to communicate with the dead, but also agreed that mediums could be frauds. She started a partnership with Houdini that would last even after he died (in a sense).

Mackenberg joined Houdini’s team in 1924. Mackenberg would adopt a costume and a backstory and meet with psychics before Houdini came to town. She took notes on their methods and passed them on to Houdini. Then when Houdini came to town, they would discredit the fake psychics publicly.

Mackenberg testified before Congress hoping to convince them to pass a bill that would outlaw predatory practices among mediums. In the process, she divulged that multiple members of Congress, as well as President Calvin Coolidge, visited mediums in Washington, D.C.

After Houdini died in 1926, she continued her work, investigating fraudulent psychics and giving talks to professional and legal groups as well as the general public on how mediums were able to successfully swindle their victims.

Before Houdini died, he gave a code to his wife and a few other people, one of whom was Mackenberg. The purpose of this was to provide proof of authenticity should any medium actually be able to communicate with his spirit. Despite trying many times, Mackenberg was never able to receive an authentic message.

Mackenberg believed in an afterlife, but the mediums she investigated were not solely providing comfort based in reality or otherwise. Mediums who met with the disguised Mackenberg charged a fee, tried to sell her stocks because of ‘advice from the beyond’ in businesses they stood to profit by, and otherwise attempted to prey upon her, and their clientele, financially and fraudulently. In her work, she advanced not only the opportunities for women in investigative fields, but also some techniques of scientific investigation that are still used today.

According to Atlas Obscura,

By the time she died in 1968, she claimed to have investigated 1,500 mediums. “Rose Mackenberg dons shabby clothes and tracks down ‘spirit world’ frauds,” the Vancouver Sun wrote of her. “She has found plenty, too, having been put in touch with 1,500 departed husbands she never had.”

For more about the indomitable Rosa Mackenberg, check out: