GRAZ, Austria, June 11, (AP): Austria fell silent for a minute on Wednesday in memory of the 10 people killed in a school shooting in Graz, which ended with the gunman taking his own life. The man's motive remained unclear. Austria has declared three days of national mourning following what appears to be the deadliest attack in its post-World War II history.

At 10 am on Wednesday, marking the moment a day earlier when police were alerted to shots at the school, the country stopped for a minute of silence. Hundreds of people lined the central square in Graz, Austria's second-biggest city. Some laid more candles and flowers in front of the city hall, adding to a growing memorial to the victims.

The first candles were laid on Tuesday evening as a crowd gathered on the square, some people hugging each other as they tried to come to terms with the tragedy. In the capital, Vienna, the local transport authority had trams, subway trains and buses stop for a minute. Police said they found a farewell letter and a non-functional pipe bomb when they searched the home of the assailant.

The 21-year-old Austrian man lived near Graz and was a former student at the BORG Dreierschützengasse high school who hadn’t completed his studies. Police have said that he used two weapons, a shotgun and a handgun, which he appeared to have owned legally. Police didn’t elaborate on investigators’ findings in a brief post on social network X.

But a senior official who acknowledged that the letter had been found on Tuesday night said it hadn’t allowed them to draw conclusions. "A farewell letter in analog and digital form was found,” Franz Ruf, the public security director at Austria’s Interior Ministry, told ORF public television. "He says goodbye to his parents. But no motive can be inferred from the farewell letter, and that is a matter for further investigations.” Asked whether the assailant had attacked victims randomly or targeted them specifically, Ruf said that is also under investigation and he didn’t want to speculate.