“Rex! Stop!” shouted the handler, but the dog did not obey.

The German Shepherd lunged at a girl in the third row, barking loudly. She was a modest, quiet student named Marie—she usually sat in the back rows. Today, she stood next to her friends, holding a notebook against her chest. At first glance, she looked like an ordinary, shy girl.

But Rex was charging at her as if he had gone mad. He growled, bared his teeth, and then jumped on her, knocking her to the floor. The girl screamed, the notebook flew, and panic erupted. The teachers tried to pull the dog