Just over a month ago, Minnesota grieved along with the rest of the nation when a New York City workplace dispute turned violent as a recently fired clothing designer gunned down a former coworker near the Empire State Building. Nine bystanders were injured as the perpetrator battled to his death with police.

On Thursday, an even more deadly episode of workplace violence shattered the tranquility of a golden-lit Twin Cities autumn afternoon. Around 4:30 p.m., gun shots echoed through the peaceful Minneapolis neighborhood that is the home of Accent Signage Systems.

Five people, including Accent's respected owner Reuven Rahamim, were fatally wounded when the gunman, an employee being terminated Thursday, opened fire with a Glock 9-millimeter semiautomatic pistol inside the firm's headquarters. Three others were injured before the shooter, Andrew Engeldinger, took his own life.

It was one of the deadliest eruptions of violence in the Twin Cities in memory. The shock, sorrow and bewilderment settling in across a metro area known for its beautiful lakes -- not mass murder -- is palpable.

"This is something we see on the news in other parts of the country, not here in Minneapolis,'' said Minneapolis Deputy Police Chief Kris Arneson in a statement that gave voice to many metro-area residents' rattled sense of security.

Investigators, who said Friday that Engeldinger had packaging for more than 10,000 rounds of ammunition at his house, are still piecing together what happened. Whether we'll ever "understand" why the crime occurred is debatable. In some ways, more details in cases such as this only deepen the painful mystery about how emotional or psychological distress, misfortune and social or workplace frictions can combine explosively in some individuals and lead to heinous acts.

At the same time, new information released Friday raised a question often heard after a violent crime: Do we do enough to help those who may be struggling with a mental illness? A mental-health advocate working with Engeldinger's family said they had tried to get him to seek treatment for possible schizophrenia.

The slayings should put a high-profile spotlight on workplace violence. While the annual number of work-related homicides has declined sharply since the 1990s, there were still 458 people murdered on the job in 2011, according to the U.S. Bureau of Labor Statistics. Most died during robberies, but 12 percent were killed by coworkers or former coworkers.

Mass shootings like the one that occurred at Accent Signage are rare, but still tragic. Each of the five victims who died at Accent Signage had families, friends, homes and plans. Their deaths are unacceptable, and are heartbreaking evidence that no community, and no company, is immune from this type of crime.

"I think most organizations take the position it'll never happen,'' said Carolyn Reinach Wolf, a New York-based mental-health attorney and consultant on the prevention of workplace violence.

Education officials have responded to another emerging crime category -- school shootings -- with violence prevention strategies and crisis-response plans. More workplaces need to follow their lead.

A 2005 U.S. Bureau of Labor Statistics report found that fewer than half of employers had a systematic approach for identifying volatile employees. The report also found that more than 70 percent of employers do not have a formal program or policy in place to address workplace violence. That's stunning when federal authorities estimate that nearly 2 million Americans are victims of workplace violence each year.

Violent crime rates are declining nationally and in Minneapolis. The Accent tragedy not only cautions us against letting down our collective guard but reminds us that crime prevention strategies should also include one of the places we feel safest -- our worksites.