"I turned around and saw a black silhouette, his face hidden by a balaclava. Suddenly he ripped it off, and I recognised him," he told the ARD television network.

"I then asked him, 'Robert, did you shoot?' The young man was silent. 'Robert, what's going on in your head?' Silence again.

"I then showed him my chest and asked him to shoot at me saying, 'but if you shoot, look into my eyes'. Then, he responded, 'for today, sir, that's enough'. I then shoved him into an empty classroom and locked the door with two turns of the key."

Soon after, Steinhauser shot himself in the head as armed police closed in.