This article examines how and why criminal proceedings were brought against alleged cases of Catholic mysticism in several European countries during modernity. In particular, it explores how criminal charges were derived from mystical experiences and shows how these charges were examined inside the courtroom. To bring a lawsuit against supposed mystics, justice systems had to reduce their mysticism to 'facts' or actions involving a breach of the law, usually fraud. Such accusations were not the main reason why alleged mystics were taken to court, however. Focusing on three representative examples, in Spain, France and Germany, I argue that 'mystic trials' had more to do with specific conflicts between the defendant and the ecclesiastical or secular authorities than with public concern regarding pretence of the supernatural. Criminal courts in Europe approached such cases in a similar way. Just as in ecclesiastical inquiries, during the trials, judges called upon expert testimony to debunk the allegedly supernatural. Once a mystic entered the courtroom, his or her reputation was profoundly affected. Criminal lawsuits had a certain 'demystifying power' and were effective in stifling the fervour surrounding the alleged mystics. All in all, mystic trials offer a rich example of the ways in which modern criminal justice dealt with increasing enthusiasm for the supernatural during the 19th century.