Yao Jiaxin on court.

During the trial, Yao's lawyer argued that Yao committed the killing "in the heat of passion" and pleaded for leniency, saying "depression was to blame, to some extent, for the killing."

Previous media reports said Yao was forced by his parents to practice piano, which resulted in him occasionally smashing the piano keys to vent his anger. Yao's lawyer claimed that he might have "mechanically" stabbed Zhang several times because of this habit.

This claim was rejected by the court at the first trial.

About a hundred people, including journalists, students and relatives of Yao and Zhang, attended Friday's court hearing.