It happened years ago, but the scene is still fresh in Carol's mind: Her onetime boss pinning one of his young employees against a wall in a conference room and landing multiple punches on her face.
From her nearby desk, Carol, who asked that her real name not be used, saw it all.
"He just went into the most violent rage that I'd ever seen in my life," she said. "There was blood everywhere."
At the time, Carol worked at a medical school that is part of Yale University, which recently saw the murder of one of its graduate students, Annie Le, allegedly at the hands of a co-worker at a university lab.
The murder has raised new questions about workplace violence across the country and brought back painful memories to people like Carol, who quit Yale Medical School shortly after the incident she witnessed in the summer of 1999. (A current employee at the medical school, who also asked not to be named, and Yale's clerical workers' union confirmed the incident. Yale University and New Haven police did not immediately return calls from ABCNews.com. UPDATE Wednesday, Sept. 23: In a report provided to ABCNews.com by New Haven Police, the man accused of the beating said that the injured employee lunged at him after a disagreement and that he was defending himself. A police detective investigating the case concluded that the man was telling the truth.)
Despite the headlines, statistics show that workplace violence is still uncommon.
"If you look at workplace homicides in any one year, they're typically at 1,000 or under, across the whole U.S., among 150 million workers," said Tom Tripp, a Washington State University management professor and co-author, with Georgetown University management professor Robert Bies, of "Getting Even: The Truth About Workplace Revenge."
"That's a thousand too many," Tripp said, "but statistically speaking, it's really rare."
Incidents of workplace violence other than murder are quite high. In a 2005 survey of 7.1 million private businesses, the Bureau of Labor Statistics found that 5 percent -- more than 350,000 businesses -- reported workplace violence in the 12 months before the survey.
But Tripp noted that the definition of workplace violence used by various studies is more expansive than some might think: It can include verbal threats and bullying, as well as physical acts. Oftentimes, the perpetrators of workplace violence are not the workers themselves but rather third-parties, such as robbers, customers or aggrieved spouses.
"A very small percentage of it is by co-workers," he said.
Washington State's management professor Tripp said employees can take steps to prevent violence among co-workers by making sure they report all threats to their superiors or police. Employers, meanwhile, he said, should establish systems to address employee complaints.
Carol, the former Yale employee, said that in retrospect, there were signs that the supervisor could be dangerous.
He was "moody" and hostile, she said, and frequently called people by offensive, obscene names.
Raymond Clark, who was arrested in the Le case, was described by some as a "control freak" who was upset at how Le handled mice at the lab where they worked.
But Tripp said that many people who exhibit hostile behavior in the workplace never do turn violent, while some who commit violent acts show no warning signs.