Born on January 30, 1976, in Danderyd, Sweden, Karl Helge Hampus Hellekant, later Karl Svensson, became involved in the neo-Nazi movement during his youth. He was associated with the Swedish fascist organization Nationell Ungdom (National Youth), which espoused white supremacist and anti-immigrant ideologies. Hellekant and his associates compiled "death lists" containing over 1,200 names of individuals they deemed enemies, including journalists, politicians, and activists.

On October 12, 1999, Hellekant, along with accomplices Björn Lindberg-Hernlund and Jimmy Niklasson, went to Söderberg's apartment in Sätra, Stockholm. Hellekant fatally shot Söderberg multiple times, including in the head. The murder was a direct retaliation for Söderberg's exposure of neo-Nazi infiltration into labor unions.

Hellekant was arrested shortly after the murder and, in 2000, was convicted and sentenced to 11 years in prison. His accomplices also received prison sentences for their roles in the crime. The murder was declared a hate crime, highlighting the dangers posed by extremist ideologies.

While incarcerated, Hellekant was involved in a 2005 incident where he assisted a fellow inmate in an escape attempt. Despite this, he was released on probation in February 2007