Study finds distinct patterns lead to domestic partner homicide

A new study has explored the complex patterns which lead to an intimate partner homicide (IPH), in an effort to better understand and prevent the tragic event happening.

The research delved into the criminal careers of people who had been involved in at least one incidence of lethal and non-lethal intimate partner violence in Quebec, Canada, over three decades.

Statistics indicate that approximately 20 per cent of all homicides in the country are attributed to IPH. 

Co-author, Dr Sarah Paquette from the University of Portsmouth’s Department of Psychology, said: “Intimate partner homicide is the ultimate manifestation of a spectrum of violence within current or past relationships. 

“The fact that this type of killing makes up a fifth of all murders in Canada means understanding the predictors and risk factors of the crime is a matter of life or death.”

The study, published in The British Journal of Criminology, gathered insights from a database of criminal events recorded by police in the Quebec province between 1990 and 2022. It includes information on offenders’ criminal careers as well as crime characteristics.

175,985 individuals had been involved in at least one incidence of intimate partner violence during this time. Of these, 1,219 had either attempted to, or killed their partner.

Researchers examined a random sample of 1,276 offenders, who were mostly men (87 per cent). 276 had killed their partner (92 per cent men), while the other 1,000 had a history of violence against them. 

The team found similar characteristics between individuals who committed lethal and non-lethal violence towards their partner. On average, offenders committed two incidents of violence against their partner and 7 other criminal events, with the first event happening in their early 30s. 

Factors associated with intimate partner homicide include violent criminal history and repetition of criminal acts. Both male and female IPH offenders used sharp weapons, with patterns suggesting various motives including self-defence, fear, and anger.

The findings also suggest the likelihood of an intimate partner homicide is stable over a criminal career.

There were two distinct categories of violence that indicated how long until an intimate partner homicide was committed. The first was severe violence – such as sexual assaults and physical violence – which would result in the victim’s death early in the offender’s criminal career. The second was chronic violence, where there was a persistent pattern of aggression and abuse over an extended period and the death occurred after a longer period of time. 

“The objective of this study was to expand understanding of intimate partner homicide”, added Dr Paquette. 

"Our findings show severe episodes of intimate partner violence increase short-term risk of IPH, while repeated instances of various violent episodes heighten mid-to long-term risk. Law enforcement agencies can utilise this knowledge to develop targeted prevention strategies.”

The study was a collaboration between the University of Portsmouth in England, led by Dr Chopin from University of Lausanne in Switzerland, and academics from the University of Montreal and the Quebec Provincial Police in Canada.

The authors acknowledge several limitations to the research, including regional specificity and the exclusion of broader social and environmental factors. They recommend future work to address these gaps and further refine predictive models for intimate partner homicide.