Exclusive: Stalking, sexual violence were precursors to murder, police find in landmark study

The Korean National Police Agency has launched a research project to identify common patterns among relationship-based crimes, as killings of wives, former partners and relatives continue to occur this year. With such crimes showing no sign of abating — and growing in brutality — while gaps in victim protection systems are repeatedly exposed, the findings of the study are drawing close attention.

The agency is conducting the research, titled "Statistical Analysis of Acts Preceding Homicide," through an external research institution.

The study aims to identify cases in which murder suspects had previously committed relationship-based offenses, in hopes of finding clues for preventing future harm. Researchers are screening murder suspects investigated by police who had prior records of offenses covered under the Act on the Prevention of Violence Against Women — including domestic violence, intimate partner violence, stalking, sexual violence and prostitution-related crimes — and analyzing common characteristics such as the nature of the incidents and the suspects' social backgrounds.

Police said they are taking a broad look at suspects' histories of violence against women. "We are screening and analyzing suspects who either had a prior record of reporting violence against women or whose involvement in such violence was confirmed during the investigation," a police official said. "We are also researching factors that can help identify warning signs, including risk factors and crime-triggering factors specific to each suspect."

"If there was a prior act such as a victim reporting violence against women, the victim should not end up dead afterward," the official added. "The data will be used going forward to assess the danger posed by suspects in order to prevent such harm."

The analysis also encompasses a broad range of social background factors, including suspects' age and occupation, the official said. Final results from the research are expected by the end of this year.

The study represents a full-scale statistical analysis following the police's comprehensive measures on relationship-based crimes announced in July last year. At the time of that announcement, police had conducted an internal analysis of 70 cases — out of 388 homicides and attempted homicides recorded between January and July 2025 — in which suspects had prior records of domestic violence, intimate partner violence or stalking.

That analysis found that 59 suspects (84 percent) were male and 11 (15 percent) were female. By offense type, domestic violence accounted for the largest share at 39 cases (55.7 percent), followed by intimate partner violence at 18 cases (25.7 percent), stalking at 9 cases (12.8 percent), sexual violence at 3 cases (4.3 percent) and prostitution-related offenses at 1 case (1.5 percent).

Some crimes occurred with no prior report or investigation on record. Of the 70 cases, 40 (50.7 percent) involved suspects with no prior reporting or investigation history. In 24 cases (34.2 percent), suspects had been reported or investigated only once or twice before.

In 40 cases (57.1 percent), suspects had no prior criminal record or only one previous offense, indicating a high proportion of first-time offenders. Police at the time attributed this to the nature of relationship-based crimes, noting that victims often hesitate to report such offenses and that these crimes can escalate to serious violence rapidly.

Starting this month, police will receive residential information on released violent offenders from the Ministry of Justice and incorporate it into patrol operations. The data will be integrated into Pre-CAS, the police's crime-risk prediction and analysis system — expanding its use from investigative functions alone to crime prevention as well.

Pre-CAS serves as the eyes and ears of officers on patrol, accessible through dedicated terminals. Police use it to analyze crime occurrence data, 112 emergency call records and the status of crime-prevention facilities, drawing on the information to plan patrol routes.

The residences of released violent offenders will be displayed on a map, allowing police to identify areas of concentration and plan patrol routes accordingly. The seven offense categories whose released offenders will be tracked — classified as high-risk for recidivism — are murder, arson, kidnapping, robbery, theft, organized crime and drug offenses.

Police said the primary purpose of linking the residential data is to prevent reoffending, with the prevention of repeat relationship-based crimes also among the stated goals.

"Since recidivism prevention is included in national policy priorities, we reflected the information in Pre-CAS to share data across agencies and prevent reoffending in cases where violent criminals pose a risk of committing further crimes," a police official said.