Stunned nation observes minute’s silence, mourners line central square in Graz where 10 people were shot dead at local school.

Austrian police investigating a school mass shooting in the city of Graz this week said they had found discarded plans for a bomb attack at the suspect’s home, as the grief-stricken country embarked on three days of national mourning.

Investigators said on Wednesday that they had discovered abandoned plans for a bombing, a non-functional pipe bomb and a farewell letter and video during a search of the home of the dead suspect, who shot dead 10 people during the previous day’s rampage at the city’s BORG Dreierschützengasse high school, before pulling the trigger on himself in a school toilet.

Police said the 21-year-old, a former student of the school, had acted alone, his farewell note revealing no motive for the attack. Austrian media reported the suspected gunman had been bullied at school, but police have not confirmed that as of yet.

The mass shooting killed nine students – six girls and three boys aged between 14 and 17, one of whom had Polish citizenship – as well as a teacher, leaving 11 wounded.