“Does a normal human understanding not tell us that a continual consumption of such products causes damage?” he asked during his speech. “This kind of market development should be stopped.”

Köhler sat in the Catholic St. Borromäus church in the Baden-Württemberg town where ten days ago Tim Kretschmer began the massacre in which he shot dead 15 people, including nine children at his former school, before killing himself.

Detectives working on the case have said that the evening before the massacre Kretschmer played the violent shooter game “Far Cry” on his computer for at least two hours. His father had kept more than a dozen guns and thousands of rounds of ammunition in the house. Kretschmer took a pistol and around 200 rounds from his home when he went on his killing spree.

“All of Germany mourns with you,” Köhler told the assembled locals. He was joined by Chancellor Angela Merkel, Foreign Minister Frank-Walter Steinmeier and the entire Baden-Württemberg state government.

While white candles with the names of those killed were carried to the front of the church, Köhler also mentioned the death of Kretschmer himself. “A young person has killed 15 others, and then himself,” he said. “He plunged families into sorrow and desperation – his own too. They too have lost a child. For them too a world has collapsed.”

Winnenden town centre was mostly closed down for the service, and the thousands of people who gathered to take part in, or watch, the church memorial.

Initial expectations that up to 100,000 people would show up were quickly revised, and in the end the police said around 7,500 people came to pay their respects Some gathered in the seven other nearby communities where the victims had lived.