Several serial killers have a history of animal cruelty. Not everyone who is cruel to animals becomes a serial killer but many have an underlying psychopathology.
Macdonald reported a triad for predicting of violent tendencies:
(1) cruelty to animals
(2) obsession with fire setting
(3) persistent bedwetting past the age of 5 (with presumed risk of social ridicule)
There is a risk of a post hoc fallacy if causality is inferred.
A screen for a serial killer might include the presence of 2 or more of the following:
(1) The person enjoys and fantasizes about torturing and killing animals.
(2) The person engages in a repetitive animal cruelty with progression in species and/or cruelty.
(3) The person has a history of abuse as a child.
(4) The person engages in other antisocial behaviors such as arson or violent crimes.
(5) The person has a problem with substance abuse.
(6) The person does not feel remorse after behaving badly.
