"Many people look at workplace killers and mass murderers and say oh, they just suddenly snap and go berserk," James Alan Fox, Ph.D., Lipman Professor of Criminal Justice at Northeastern University, said in the documentary. "That's myth."

"Murder by Proxy: How America Went Postal" is framed around the notorious U.S. Postal Service (USPS) shootings in the 80s and 90s. The film highlights the 1986 Edmond, Okla., murders, where letter carrier Patrick Sherrill killed 14 people, and the 1991 Royal Oak, Mich., shooting, where Thomas McIlvane, a terminated USPS employee, killed four. The postal service shootings sparked a national conversation, including the phrase "going postal," which was coined in the late 1980s to convey violence.

Going Postal

The documentary follows Charlie Withers, a Royal Oak post office letter carrier and union steward who was present during the deadly Nov. 14, 1991, shooting, as he traveled to Washington state in 2008 to urge lawmakers to pass legislation designed to curb abuses in the workplace.

Withers has worked as a letter carrier since 1975. While productivity was always important, he said it became a much more prominent issue later in his career as his superiors made a bigger push for more output, ultimately creating a toxic work environment.

"Managers took power that they had and did what they wanted with it. As long as they got the numbers, as long as they pleased the people above them, they could do it," he said.

The national spotlight fell on USPS during and following the shootings. In the documentary, former USPS employees described difficult management and a toxic work environment while William J. Henderson, who served as USPS Postmaster General from1998-2001, defended USPS.

"We did a study that was published in the year 2000 when I was postmaster general that showed that the incidence of violence in the postal service wasn't any greater than it was anywhere else," said Henderson. "Going postal was a myth."

Fox countered that the USPS study did not distinguish between murders committed by employees (or former employees) and those committed by customers. "If you only look at episodes involving the postal service and their employees, then indeed they have a higher rate," he said.

Addressing Workplace Violence

"Murder by Proxy" describes several workplace shootings performed by employees who recently had been terminated. The film points out that terminated workers often lose a lot more than just their paychecks: a pink slip also can mean a loss of self-worth and a social network. Terminated employees who feel alienated and believe the company treated them poorly may be at a particular risk for taking such drastic action.

Unfortunately, no guide exists to help employers pinpoint the workers who might turn to violence. Fox calls potential warning signs "yellow flags, which only turn to red flags after the blood has spilled." Companies would like to create a checklist to identify the workers they believe are the "bad apples," but unfortunately, no such guide exists.

"No one has ever and will ever come up with a profile of workplace murder that's sufficiently predictive" [to use] to screen employees," Fox asserted.

As a result, companies often fail to address the larger issue surrounding workplace violence.

"In the aftermath of a shooting that gets widespread attention around America, what do companies do? They hire a consultant. They come up with a checklist. They do a little training or two. They don't really suggest, 'Let's just look at our workplace, what is toxic here, and let's fix those issues,'" Fox explained.

As the documentary pointed out in its closing moments – after revealing that the Washington state bill Withers supported did not pass – workplace violence is an issue of increasing concern. In fact, 70 percent of Americans apparently are unhappy in their jobs. The film pointed to possibilities even deadlier than mass workplace shootings: insider sabotage.

"Sabotage could be even more deadly and a greater risk to our safety than bringing a gun to work," Fox said. "It could be poisoning products, creating environmental contaminants … These are all the kinds of things that we need to worry about, and ensure that we don't have workplaces full of people who are angry, bitter and feel resentful."

For more information about the documentary, visit http://murderbyproxyfilm.com.