Austrian school shooter planned attack in detail but his motive remains unclear, investigators say

People light candles for victims of a former student who opened fire at a school, fatally wounding 10 people and injuring many others before taking his own life, in Graz, Austria, Tuesday, June 10, 2025. (AP Photo/Darko Bandic)

GRAZ, Austria -- The former student who killed nine students and a teacher at a school in Austria and then took his own life planned the attack in detail, but he appears to have shot his victims at random and investigators still haven’t been able to ascertain his motive, officials said Thursday.

The 21-year-old had left the BORG Dreierschutzengasse high school in Graz three years ago, breaking off his studies after attending for three years, police said. They said they knew of no personal connection between the gunman and the students he shot, but that one of the two teachers he shot had once taught him. They were still investigating whether that was a factor.

The attack prompted Austria to declare three days of national mourning, and large numbers of candles have been laid in Graz’s main square and outside the school.

The assailant, an Austrian who lived with his mother near Graz and whom officials have declined to identify, used a Mercury double-barreled shotgun and a Glock 19 handgun in the shooting. Michael Lohnegger, the head of Styria province’s criminal police office, said that he arrived at the school Tuesday morning with a backpack containing the weapons, and put on equipment including shooting glasses and a headset in a bathroom before starting a roughly seven-minute shooting spree.

He opened fire indiscriminately on the building’s third floor before shooting open the locked door of a fourth-floor classroom and again firing indiscriminately, Lohnegger told a news conference. Lohnegger said that he had enough ammunition to continue shooting and it was unclear why he hadn’t; the assailant then returned to the bathroom and shot himself fatally in the head.

A search of his home uncovered a farewell letter and video, which Lohnegger said added up to “an apology directed to his family for the crime and a general thank-you,” but offered no “indication for a motive.”

They also found a handwritten note that showed he had planned the attack “down to the smallest detail” -- setting out how he would proceed, but giving no date for the crime. It suggested that he had lacked enough time to build a fully functional pipe bomb, and investigators found one that wouldn’t have worked.

Lohnegger said a picture had emerged of “a very introverted person” who largely didn’t take part in real-world activities, and that his great passion was taking part in online first-person shooter games.

“But even here, there is no information from his personal surroundings that he ever expressed any anger or resentment toward the school, students or teachers,” he added. The man had no previous police record and “there were definitely no particular problems with him at this school.”

The shooter was in unspecified vocational training at the time of the attack, investigators said.

He had bought the shotgun legally in Graz in early April, and the handgun from another shop in the city in late May. He had a license to own weapons that required a report from a psychological expert, which apparently was produced in March.

Starting in March, he took part in shooting practice five times at a shooting club in Graz, using a hired firearm, Lohnegger said.

The slain students were six girls and three boys aged between 14 and 17. Eleven people were wounded in the attack, and authorities said on Wednesday that their lives weren’t in danger.

By Philipp Jenne, The Associated Press

Associated Press writer Geir Moulson in Berlin contributed to this report.