Sean P. Mactire

Sean P. Mactire is an American crime writer, criminology researcher, and child-abuse-prevention advocate, best known to fiction writers as the author of Malicious Intent: A Writer's Guide to How Murderers, Robbers, Rapists, and Other Criminals Think (Writer's Digest, 1995), a long-running title in the Howdunit reference series for mystery and crime writers. He is also the author of Victims of Domestic Violence and Lyme Disease and Other Pest-Borne Illnesses, and his working background in child-protection and victim-advocacy work informs the more clinical chapters of his criminal-psychology reference.

Malicious Intent takes mystery writers inside the working mind of the criminal: who these people are, why they commit their crimes, how they choose their victims, and how investigators catch them. It opens with a historical survey of crime running back to 1500 B.C., works through the creation of organized police forces and the way that institutional change shifted criminal activity from open assault toward cunning and secret operations, and then moves through the psychology of modern offenders and the working development of psychological profiling. Major sections cover serial murder, cult-related murder, terrorism, sexual predators, child molesters and child murder, the role of substance abuse in criminal behavior, and the role played by the victim. Each topic is documented with case studies drawn from real criminal careers, with the argument that working fiction writers should build their villains from the fact patterns of actual offenders rather than from genre stock characters.

The book has been on writing-reference shelves for more than three decades and is regularly cited alongside Keith D. Wilson's Cause of Death, Anne Wingate's Scene of the Crime, and Russell Bintliff's Police Procedural as the foundational Howdunit references. It remains in print and is widely used by both fiction writers and true-crime researchers.