Fear should never have the last word. "I feel the vibrations of the explosion and relive the moment when talking about it," says Arif Sagdic, apologizing for his nervousness with a slightly lowered gaze.

But Sagdic nevertheless still finds the strength to talk about the attack he survived, which was perpetrated by the National Socialist Underground (NSU), a neo-Nazi terrorist group. The audience at the commemorative event in Cologne is on the edge of their seats listening to Sagdic speak.

"When I heard the explosion, I threw myself on the ground," recalls the Turkish-born Sagdic, the owner of a hardware store on Keupstrasse in Cologne. "The shop window was shattered, just like those at the hairdresser's opposite — it was as if there had been an earthquake. People were lying in their own blood. People were screaming. I could pick that up even though I could barely hear from my left ear."

NSU trial: Many questions remain unanswered

More than 20 people were injured in the bomb attacks on Keupstrasse in 2004 and Probsteigasse in 2001 in the western city of Cologne. Ten murders and 15 robberies are also part of the cruel chronicle of the extreme-right terrorist NSU. The group was not caught until 2011.

The trial against the NSU ended in the summer of 2018 in Munich. Group member Beate Zschäpe was given a life sentence; her co-conspirators Uwe Mundlos and Uwe Böhnhardt had died in an apparent murder-suicide in 2011.

Even after the yearslong investigation and trial, there are many unanswered questions: Who supported the NSU trio on the ground? Why did it take investigators so many years to link the victims? Were they ignored due to their immigrant origins? Why did it take investigators so long to discover the right-wing extremist group?

"We were not even allowed to be victims," said Semiya Simsek, daughter of the murdered florist Enver Simsek, at a memorial service for the NSU victims held in Berlin in 2012.

"It was like an earthquake": The scene of the 2004 Keupstrasse bombing in Cologne

'The investigation was worse than the attack'

Sagdic also speaks of strain and false suspicions after the bomb attack in Keupstrasse: "Of course the attack was bad, but we thought the wounds would heal again, and we were glad that nobody died."

But during the police questioning, he felt intimidated: "I said that I think neo-Nazis were behind the attack. The officer then just held his finger to his lips, and he didn't seem to want to hear anything more about it," recalls Sagdic.

For months, he felt haunted by the memory of the attack on his way home from work. "Fear became my constant companion. I could not even talk to my wife about it until five years later."

Read more: Neo-Nazi terror trial is a failure for Germany

Arif Sagdic (r.), survivor of an attack by NSU neo-Nazi terrorists, with Kutlu Yurtseven and Charlotte Schwalb of the "Keupstrasse is everywhere" remembrance initiative

Even after the attack in Cologne's Probsteigasse on January 19, 2001, it was still the victims of the NSU attacks who were initially suspected as perpetrators, says Kutlu Yurtseven, an actor and musician who is one of the founders of the initiative "Keupstrasse is everywhere," which held the commemorative event for victims of the NSU. The event coincided with the anniversary of the January 19 attack, when a bomb exploded in a grocery store of an Iranian family, seriously injuring the then-19-year-old daughter of the shop owner.

"The father very quickly became the focus of the investigation. Suddenly the blame seemed to be pointed at him. Even his brother was brought into the picture. There was talk of gambling debts, extortion for protection money and so on," recalls Yurtseven.

The Keupstrasse initiative campaigns against racism and xenophobia, and supports NSU victims and their families. Yurtseven knew the Iranian family well after "three years of eating from their store," he says, and the office of his music label was directly above the shop. But the family quickly moved away. It was not until many years later that it became known that the NSU was behind the attack.

Read more: NSU verdict sparks protests, calls for investigation into police complicity

Signs reading "For a society without racism" and "NSU Terror: The state and Nazis hand in hand" at a 2015 Munich demonstration organized by the "Keupstrasse is everywhere" initiative

Openness and courage against racism

The ghost of the NSU lives on, even after the end of the lengthy trial. Yurtseven says that Turkish-born lawyer Seda Basay Yildiz, who represented one of the victim families in the NSU trial, received threatening letters signed "NSU 2.0."

The lawyer told DW in an interview that one of the threatening letters read: "What you did to our police colleagues will have consequences for you" — a clear indication of the involvement of the authorities.

The "silence of the mainstream" about such threats is dangerous, warns Yurtseven, as is the "silence about the criminalization of victims."

But "I won't stay silent," says Sagdic as his listeners break into applause. "That I have learned in Germany: As long as you say nothing, nothing changes." Even if talking about the attack and the consequences is painful.

Read more: Racism is socially acceptable in Germany, says lawyer in neo-Nazi trial

When the audience asks him about his family, he has tears in his eyes: "My son was three years old at the time; I'm sorry that I couldn't really be there for him then as I would have liked." He leaves the room for a few minutes, then returns and says in a resolute voice: "Today my son Orhan is 1.9 meters tall (6 feet, 2 inches). He takes me into his arms — with my mere 1.6 meters — and says: 'Everything is OK; I am fine.' I can talk openly with him about what happened."

Orhan, now almost 18, often accompanies his father to events where he speaks publicly about the Nazi terror and warns of the consequences of racism and xenophobia. Because for Arif Sagdic, fear must not have the last word.