On June 27, 2001, Ali Taşköprü drove to the market in Hamburg to buy cigarettes. When he returned to his family’s store he noticed a dark liquid on the floor: a pool of blood. Behind the counter lay his son Süleyman. “I put his head in my lap,” he said afterward. “He was trying to tell me something, but he couldn’t anymore.” It would take ten years for Taşköprü, a Turkish-German who had lived in Germany for decades, to find out what happened to his son.

The mystery began to unravel with a seemingly unrelated incident. On November 4, 2011, police closed in on a trailer in Eisenach used by Uwe Mundlos and Uwe Böhnhardt, who they suspected had robbed a bank nearby. When the police arrived, Mundlos and Böhnhardt killed themselves and set fire to the trailer. Hours later, a woman named Beate Zschäpe set fire to an apartment in Zwickau that she had shared with the two men, and fled. On the run, Zschäpe mailed out several copies of a video claiming responsibility for a slew of killings and bombings stretching from 1999 to 2007—including the murder of Süleyman Taşköprü.

The video, a ghoulish document that combined footage from the crime scenes with jokey bits involving the Pink Panther, made clear that these events were part of a campaign of rightwing terror that had never been recognized as such by authorities when it was unfolding. Zschäpe’s neo-Nazi group, which called itself the National Socialist Underground (NSU), had murdered ten people throughout Germany and maimed many others.

With the exception of a policewoman, all the victims were gunned down execution-style in their places of business in broad daylight, with the same Ceska pistol fitted with a silencer. Eight of the victims were Turkish or German citizens of Turkish background (one was Greek). The policewoman, Michèle Kiesewetter, was the only victim the terrorists would have considered “authentically” German. The NSU also set off a bomb at a Turkish café in Nuremberg in 1998, and two more bombs in immigrant areas in Cologne in 2001 and 2004. They committed at least 15 bank robberies to finance their life underground.

When Zschäpe’s video was released, the awful scope of the NSU’s terror campaign shocked the country. Chancellor Angela Merkel met with the victims’ families to offer apologies. German media framed the NSU’s actions as a national shame. The Bundestag and the German state parliaments convened investigative committees to find out why the police were unable to connect the dots on a neo-Nazi killing spree. A trilogy of movies aired on national public television, while plaques and memorials mark many of the crime scenes. Hamburg even renamed a street after Süleyman Taşköprü.