Because of her investigative work, Mackenberg became an expert on the practices of fraudulent psychics.
She claimed to have investigated over 1,000 mediums and never found one who was not a fraud.
For example, the various mediums had claimed to communicate with over three dozen non-existent deceased husbands, despite Mackenberg being single.
According to William Lindsay Gresham,  Julien Proskauer credited Mackenberg for "much of his material" in his book The Dead Do Not Talk.
Because of her investigative work, Mackenberg became an expert on the practices of fraudulent psychics. She claimed to have investigated over 1,000 mediums and never found one who was not a fraud. For example, the various mediums had claimed to communicate with over three dozen non-existent deceased husbands, despite Mackenberg being single. According to William Lindsay Gresham,  Julien Proskauer credited Mackenberg for "much of his material" in his book The Dead Do Not Talk.
Rose Mackenberg