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.

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