What was it that led a wealthy designer to drive his camper van into a crowd on a sunny spring afternoon? That's the question tormenting Münster's residents as they struggle to come to terms with Saturday's attack.
Three days on, very little is yet known about attacker Jens R.'s motives. Police have so far only been able to rule out possible incentives. They've found no evidence he was driven by any political or religious ideology.
Instead, a picture is building of a man suffering from serious mental health problems. A man who had hinted at having suicidal thoughts in an email to acquaintances and had run-ins with the law. Precious little, though, points to any plan to carry out his murderous rampage in the peaceful streets of Münster's old town.
For those living in the northwestern German city, it's that lack of clarity that is making the senselessness of the attack feel even sharper.
It's the reason the word "warum," or "why," looks down on the vast collection of candles and flowers left at the scene of the violence.
"My neighbor's daughter witnessed the attack," one woman told DW after laying flowers at the site. "She hasn't stopped crying ... I don't understand how this could have happened."
"It's unbelievable, there are no words," another local resident, Julia Hoefer, told DW.
She says she came to the scene in the hope that it would help her "accept and process" what's happened here — an area of the city she says she considers the heart of Münster. But as she chokes back tears, its clear it is going to take her, like many others, a lot longer before they have any sense of closure.
And yet, it is the unity among the city's residents that is the one ray of light, shining through the horror.
In the aftermath of the attack, many people responded to a call for blood donations from the city's hospital. Queues of locals lined up to do their bit to help the injured.
Remembering the victims
Hundreds more crowded into the city's iconic cathedral on Sunday evening to take part in a standing room-only service remembering the two people who lost their lives in the attack, in addition to the driver. Among those attending the memorial were the relatives of victims, witnesses and the emergency response personnel who were first at the scene.
Then there were the 250 additional hospital staff from the city's university clinic who rushed to work on Saturday evening, after getting the call many hoped they never would. Hospital officials say its very likely they saved lives that night.
It's this spirit that's winning praise from the city's mayor, to its bishop, to those leaving messages of condolences beside the memorial at the scene of the accident.
This is a city defiant in the face of violence.