Clearly, you have both the right and the responsibility to intervene if you see behavior that is threatening or violent, or that you, in good faith believe might lead to threats and violence. This is an area where being proactive is always a good idea. Don't wait until it's too late. While actual incidents of violence may be rare, when one happens, the consequences are so grave that you must take action ahead of the curve.
Experts agree that effective pre-employment background checks are crucial. Before hiring any applicant, check references and ask specifically if there is any history of violent or harassing behavior. Even if the references refuse to answer the question, you have taken reasonable steps to screen out potentially violent employees and that will help you if you're ever sued.
Once you've hired employees, you have an obligation to provide a safe workplace. You want to create a violence-free environment.
Lynne Eisaguirre is a former practicing employment attorney whose media credits include CNN Headline News, ABC News, Bloomberg TV, U.S. News & World Reports, The Boston Globe and The San Francisco Chronicle, among many others. She presents speeches and workshops on management issues to clients such as Bristol Myers Squibb, Harley Davidson, Sun Microsystems and Southwest Airlines. You can reach Lynne at http://www.workplacesthatwork.com.