"It is noteworthy that primarily girls were killed – eight girls and one boy ... The teachers killed were women," said Heribert Rech, interior minister of the southern state of Baden-Württemberg where the slaughter took place.
"I don't want to speculate too much about this at this point ... The pupils sitting nearest the door were girls," he said.
Rech also said that police did not have "sufficient indications" on the possible motives of the 17-year-old killer, who shot himself in a firefight with police after a dramatic manhunt involving hundreds of officers.
As well as the 12 killed at the Albertville school in Winnenden, the teenager, named as Tim Kretschmer, also shot dead three passers-by. Two police officers were also seriously injured.
But the death toll could have been much higher, police said at an evening press conference. They revealed that Kretschmer had been carrying more than 100 bullets for the 9mm Beretta semi-automatic pistol he had used in the massacre.
The gun was apparently taken from his father’s bedroom, as was the ammunition. Rech said the father is a member of a local shooting club and legally owns 15 firearms – 14 of which were locked in a safe.
Kretschmer had been a pupil at the secondary school until last year when he graduated, achieving "average" marks in his school-leaving certificate, Rech said.
He then enrolled in a course training to be a salesman. He also regularly worked out at the gym and belonged to a sports club. "He was described as reserved," Rech added.
By Wednesday evening, Winnenden, some 20 kilometres from Stuttgart, was still trying to come to terms with the bloodbath.
Hannes Pashak, 16, recalled getting a mobile phone call from his panicked brother Ivo, who survived the shooting.
"He told me there was blood everywhere and he was scared. He also said he simply didn't understand what had happened," Hannes said.
Hans Ulrich Stuiber, an onlooker, described the scenes of anguish and misery in front of the school, as parents sought desperately to contact their children inside.
"All teenagers have mobile phones and they quickly rang their parents," he said. "But after a few minutes, no-one could get a signal."
Parents were kept away from the bullet-ridden school until well after the killer had gone on the run. "Some were struck dumb, others were crying and a few had fainted," Stuiber said.
Around 30 psychologists rushed to the scene, treating shocked parents and pupils alike. Three counselling centres were set up in classrooms but most of the pupils chose to go home with their parents.
Ask dusk fell, Winnenden still seemed to be in a state of shock. Only policemen in green uniforms were still on the streets, the commandos in black camouflage long since back in their barracks.