Also used as a plot device in one of the amazing Lord Darcy stories, by Randall Garrett. A detective and his Watson in a medieval setting where magic is not par

Also used as a plot device in one of the amazing Lord Darcy stories, by Randall Garrett. A detective and his Watson in a medieval setting where magic is not particularly magical, but actually forensic science. They obtain a very clear image of the murderer from the victim using a spell, but it doesn't resemble any of the possible perpetrators.