Jennifer Sanmarco, who had left her job as a clerk three years ago at the Goleta, California, facility, fatally shot six postal employees before turning the gun on herself. Based on a psychological evaluation, she was on "involuntary" medical disability retirement, says Don Smeraldi, a U.S. Postal Service spokesman. Sanmarco gained access to the processing and distribution center by using the key card of a worker she held at gunpoint.

Investigators are still piecing together Sanmarco’s actions leading up to the deadly rampage, but experts say previous cases show why organizations must recognize problems and address them head-on, and not just hope the trouble goes away.

"We’ve never seen a case where someone just snapped," says Marc McElhaney, a psychologist and director of Critical Response Associates in Atlanta. "In every single one, there are a series of events that either someone ignored or did not respond to adequately."

That’s why McElhaney, author of Aggression in the Workplace, says the No. 1 step that employers should take is to adopt an anti-violence policy, explain it to employees and make them aware of their responsibility for notifying management of "antecedent signs" of workplace violence. Employees need to know whom to tell about troublesome incidents, McElhaney says, and organizations should have threat-management teams trained in how to respond when a problem arises.

Psychologist William Berman says it’s difficult to predict workplace violence because it’s rare, but having a zero-tolerance policy helps companies spot workers in trouble. "If you limit the amount of aggression or abusive language or hostility that you tolerate, the people who can’t control themselves become more obvious and it’s easier to intervene with them," says Berman, a director at Applied Psychological Techniques in Darien, Connecticut.

Violence prevention can begin even before a candidate is hired. Berman recommends conducting background checks and asking references whether the applicant has a history of violence, abusive behavior or substance abuse.

Out of fear of lawsuits, many former employers will not give anything more than a confirmation of employment, says John Reese, marketing director for HireRight, a background checking company based in Irvine, California.

Nevertheless, he says, it is not a bad idea for a prospective employer to ask former colleagues of the candidate about their knowledge of any past incidents of workplace violence. Some recent case law suggests that a former employer could be exposed to liability for withholding factual information that could have prevented a later incident, he says.

Co-workers and employers should take all threats seriously, says Doug Kane, a former FBI agent and co-founder of Risk Control Strategies. Perpetrators often discuss their plans. "They’re telling you that for a reason. They’re crying out for help," Kane says. "If you don’t recognize that and instead think they’re just blowing off steam, you’re going to be front-page news."

Employers also risk lawsuits if they don’t take measures to prevent workplace violence. "Generally, if an employer had some type of warning signs that the employee who started the incident had a propensity for violence, then the employer likely can be held liable for anything that happens because of that employee’s behavior," says Charles Wilson, an associate with the law firm Epstein, Becker, Green, Wickliff & Hall.

Despite public perception, postal facilities are no more prone to workplace violence than anywhere else, experts say. In fact, the U.S. Postal Service studied the safety of its workplaces after several shooting. The findings, issued in August 2000, indicated that postal facilities were as safe as the average U.S. workplace.

" ‘Going postal’ is a myth, a bad rap," said the report’s introduction by Joseph Califano Jr., chairman of the U.S. Postal Service Commission on a Safe and Secure Workplace. "Postal workers are no more likely to physically assault, sexually harass or verbally abuse their co-workers than employees in the national workforce."

—Todd Henneman