Your organization counts on its supervisors to motivate employees. But that doesn't give supervisors free rein to use whatever tactics necessary. As the following case proves, you have the right, and, in fact, a duty, to set a zero-tolerance policy for bullying and violence by any supervisor, even one coming off job-protected leave.
Recent case: A poultry-farm supervisor took a leave of absence to deal with his stress. Shortly after his return, the company fired him for being verbally and physically abusive to his workers. He sued, claiming the firing was in retaliation for taking leave. During the trial, the supervisor admitted he swore and shouted at employees, even occasionally throwing turkeys at his employees to "motivate" them.
A jury sided with the company, saying it had legitimate, business-based reasons for the firing. With heightened concern about, expect judges and juries to be less tolerant of manager bullying. (Carrillo v. Zacky Farms, Fresno SupCt., 2004)