Labor authorities have determined that the suicide of a Toyota Motor Corp. employee in 2017 was due to harassment by his superior, a lawyer for the man's family said Tuesday.

The worker, who died at the age of 28, developed an adjustment disorder after he was constantly verbally abused by his superior, who had called him names like "moron" and told him, "You'd be better off dead," the lawyer said.

After completing his master's degree at the University of Tokyo, he joined the automaker in April 2015 and started designing vehicles at Toyota's headquarters in Toyota, Aichi Prefecture, in March 2016.

He took a leave of absence in July 2016 due to the adjustment disorder. Although he was assigned to another section upon returning to work that October, the superior was still seated near him, the lawyer said.

He committed suicide in his room at Toyota's employee housing in October 2017, according to the lawyer.