HOKKAIDO, May 26, 2026 (News On Japan) - Two recent murder cases in Hokkaido, in which groups of young people were accused of taking the lives of a high school girl in Asahikawa and a male university student in Ebetsu, have drawn renewed attention to the psychology behind crimes committed by groups.
Experts on juvenile crime say both incidents reflect a dangerous form of group mentality that can intensify violent behavior among young offenders.
“The common factor in these two cases is group psychology,” said Yasuyuki Deguchi, a professor at Tokyo Future University specializing in juvenile crime. “When crimes are committed as a group, strong pressure emerges to match the actions of those around you. Juveniles are especially vulnerable to this kind of peer pressure.”
According to Deguchi, young people involved in groups may fear being viewed as traitors if they refuse to participate or behave differently from others, leading them to conform even when they recognize the behavior as wrong.
Another characteristic of group crimes is that individuals may engage in actions they would never attempt alone.
“Someone who cannot do anything on their own may borrow the power of others and become emboldened,” Deguchi explained. “The desire to gain recognition from others through bold behavior can further accelerate aggressive acts.”
The two Hokkaido cases shocked the public because of the brutality allegedly carried out by multiple youths against a single victim. Specialists warn that within tightly connected peer groups, the desire for approval and fear of exclusion can overpower personal judgment, particularly among teenagers and young adults whose sense of identity is still developing.
Criminologists note that group violence among youths is often fueled not only by direct intimidation, but also by an unspoken expectation to maintain loyalty to the group. In some cases, even participants who are hesitant initially may gradually become involved as the atmosphere escalates.
The incidents have reignited debate in Japan over juvenile crime, social isolation among young people, and the growing influence of online relationships and peer networks that can intensify reckless or violent behavior.
Source: 北海道ニュースUHB
