A defense official said the man, 21, was turned down for military service after failing a psychological test. Investigators are asking how he passed another such test to obtain a gun permit.
A former student killed 10 people and then himself in a shooting in Graz on Tuesday, the police said. The authorities said a pipe bomb and a “farewell letter” were found at the shooter’s house.
A 14-year-old student was arrested after the stabbing, which happened during a bag search that had been set up as part of an effort to address concerns about increased violence in schools.
Ten people were killed in a mass shooting at a high school in Graz, the country’s second-largest city, the police said. The suspect also died, in an apparent suicide.