Criminals who exhibit homicidal ideation are more likely to commit serious crimes, according to a new study.

Matthew DeLisi, professor of sociology and criminal justice, recently published the study, stating that criminal offenders who previously exhibited homicidal thoughts are more likely to commit a crime.

Criminals who showcase these emotions before committing a crime often are some of the worst offenders.

DeLisi’s main interest in the topic stemmed from his knowledge of homicidal ideation through what he viewed clinically. But studies by criminologists about the topic were lacking. 

The study sought to “introduce homicidal ideation to the criminological literature” while exploring the association between homicidal ideation and criminal careers among federal supervised release clients in the United States.

“Homicidal ideation is an important construct that should be studied more not only for its association with murder, but as an omnibus risk factor for severe criminality,” according to the study.

DeLisi studied 865 felon’s files in order to conduct this study.

“I went through their psychological histories and any mental health treatment that they’ve had measured,” DeLisi said.

Based on his findings, about 88 percent of the criminal offenders had no evidence of homicidal ideation while about 12 percent did. Of that 12 percent, 3 percent had some indication of homicidal ideation while 9 percent had definite evidence of homicidal ideation.

DeLisi also found that offenders who lack homicidal ideation tend to be around 25 years old while those who have homicidal ideation are around 14 years old.

Homicidal ideation can tend to occur at a young age based on negative family lives. Offenders who have experienced abuse during their adolescence are more likely to harbour feelings of anger, hostility and psychopathology.

Criminal offenders who exhibit traits of homicidal ideation are prone to be antisocial, suggests the study.

Offenders who manifest traits of homicidal ideation also tend to have planned their acts of violence, often with certain victims in mind.

“Homicidal ideation is just part of these personality factors that are all very negative and very aggressive. These individuals tend to interpret everyone as very threatening so they’re very touchy, easily set off, [and have] bad tempers,” DeLisi said.

DeLisi’s hope is that, with the evidence found, the actions of criminal offenders will be easier to prevent and understand.

For instance, when a criminal offender with homicidal ideation is released from jail it would be wise to have more than one staff member completing a home visit in case the offender became violent and attempted to kill an officer, suggests DeLisi.

In the southern district of Iowa, where the data was collected, the research will be used to identify which offenders would require more care when conducting home visits.

“Homicidal ideation is not only significantly associated with murder, but also with a range of serious, violent crimes, severe psychopathology and many dimensions of the criminal careers. It is an important clinical construct whose time has come for criminology to study it in greater detail,” according to the study’s conclusion.