Investigators first suspected Meddour's boyfriend. His cap lay beside the body, he had no alibi, and the couple was known for volatile arguments. After twelve days in custody, he was released and later cleared. The investigation pivoted when police learned that on July 22, Meddour had received a visit from militants of the GIA, an Algerian Islamic organization he openly opposed. A political assassination seemed plausible. But that trail also went cold. Months of interrogations yielded no suspects. The breakthrough came not from detective work but from domestic violence.

On December 15, 1997, a 23-year-old woman walked into a Stockholm police station to report her boyfriend, a man called Vlad. He had beaten her, threatened to kill her and her child. She also revealed that Vlad had confessed to murdering someone in Keillers Park, along with his friend Jon. Her account matched the crime scene evidence precisely. Police arrested Vlad that day at his Stockholm home, where he was carrying a loaded 9mm pistol. Three days later, they apprehended Jon Nodtveidt in Gothenburg. Both men initially denied involvement. Both eventually confessed.

Jon Nodtveidt led Dissection, a band that had achieved cult status in the extreme metal underground. Black metal in the 1990s was more than music; it was a scene defined by transgression and violence. In 1991, Mayhem's Swedish vocalist Per Ohlin shot himself with a shotgun. His bandmate photographed the corpse and collected skull fragments for display. In 1992, another scene figure stabbed a gay man in a Lillehammer park. In 1993, Varg Vikernes murdered Mayhem's founder and burned churches, receiving a 21-year sentence. Against this backdrop, Nodtveidt and Vlad had founded the Misanthropic Luciferian Order, a satanic group that discussed human sacrifice.

The killers' confessions revealed the evening's arc. Nodtveidt and Vlad had been drinking and using amphetamines. Near a park known as a gay meeting place, a stranger approached them. Meddour, seeing their clothes, asked if they were Satanists and expressed curiosity about the cult. The two men led him toward Nodtveidt's apartment, but Meddour grew frightened and refused to enter. They suggested Keillers Park instead. Nodtveidt retrieved a pistol and a Taser. At the park, Vlad tried to immobilize Meddour with the Taser. When it failed, Meddour ran. A bullet to the back stopped him. A second to the head finished it. Each man blamed the other for pulling the trigger.

When police searched the suspects' homes, they found satanic altars. A human skull sat in Vlad's apartment, earning him a charge for possession of body parts. During trial, the motive remained murky: satanic ritual, hate crime, or both. Criminal inspector Lars Ohlin noted that Nodtveidt initially called it a sacrifice to Satan before retracting the statement. The Swedish police ultimately classified it as a homophobic hate crime. On September 25, 1998, both men received ten-year sentences. Nodtveidt was released early and resumed making music. In 2006, his body was found at his home, surrounded by candles and a ritual book, dead by suicide. Josef ben Meddour was buried in Algiers.