A 12-year-old student at Viertola school in Vantaa, Finland, opened fire, resulting in one fatality and two injuries.

The young shooter was quickly apprehended by authorities, in possession of a handgun registered to a family member.

Finnish leaders, including President Alexander Stubb and Prime Minister Petteri Orpo, have publicly expressed their condolences and shock over the violent event.

Due to Finland's legal system, the underage suspect cannot be arrested and will instead be referred to child welfare services.

The incident highlights the ongoing issue of gun ownership in Finland, a country with a high number of licensed firearms despite previous legislative reforms.

A national period of mourning is being observed, with flags being lowered to half-staff in honor of the victims, as the investigation into the shooting continues.

ABC News is actively covering the development of this story.