Last week, Marion Guy Williams went back to his old job one last time. He came with a shotgun and pistol.

Fired two weeks earlier, his severance pay already exhausted, the 65-year-old truck driver entered Knight Transportation in Katy on May 4, shot into a lunch room, and then went looking for his former boss, loading his weapons as he walked, authorities said. Williams soon found his former supervisor, Michael Dawid, killing the 35-year-old Katy resident before turning a gun on himself.

These fatalities represent the second co-worker-related killing in the Houston area in about five months, after the December shooting of a city waste-management supervisor during an argument with a subordinate. Tyrone Roy Auzenne, 44, was charged with the death of Michael Vaughn, 55, of Humble and is awaiting trial.

Deaths from workplace-related violence are on the rise nationally, although the overall number remains relatively small. Nationwide, 61 people were killed at their jobs by a co-worker in 2014, up from 49 in 2011, according to the most recent data from U.S. Bureau of Labor Statistics.

The increase, workplace specialists say, reflects the growing anxieties among employees as wages stagnate, living costs rise, and on-the-job pressures intensify from companies operating with leaner staffs. In some cases, companies are not sensitive enough when they lay off or dismiss workers.

More Information Reporting workplace violence concerns Here are some steps companies can take to prevent workplace violence: Set up an internal team for employees to report their concerns about co-workers who might be considering violence. Press upon employees it's their duty to report threats and other concerns. Create a culture that lets employees know they won't be punished if they come forward. Provide counseling for troubled employees. Train employees on how to respond to direct and indirect threats. Sources: Don Greenwood, president and founder of Don Greenwood & Associates and Harris Garcia, director of public safety for Houston Methodist hospital

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More often than not, people who work at a company involved in a workplace killing say they're not surprised after it happens, said Don Greenwood, president of the Houston risk and security management firm, Don Greenwood & Associates. Maybe they picked up the seething rage about managers playing favorites or overheard threats against co-workers. Or possibly they listened to enough one-sided phone conversations to know there was strife at home.

"Anytime people are stressed because of economic circumstances, it can spark tendencies to commit violence," Greenwood said.

While oil companies have laid off thousands of employees over the past few months in response to lower oil prices, Greenwood doesn't expect to see an increase in workplace violence in the industry. The energy business is cyclical, and layoffs are part of the common experience, he said.

The danger comes when workers believe they'll have their jobs until they retire, said Greenwood. Sometimes the anger is triggered when a company is acquired and longtime employees lose their jobs. Other times, longtime contract workers expecting to be converted to regular employees are shattered when they get pink slips instead.

"It's hard for employees to understand that permanent employment is a thing of the past," he said.

'Long memories'

Companies can help prevent workplace violence by treating people well, especially on the way out the door, security experts said. Some of the best-run companies warn employees in advance of cutbacks so workers can prepare.

Workers shouldn't be surprised about a termination, whether it's due to a downturn in the company's financial fortunes or poor performance, workplace specialists said. In either case, they should be treated with sensitivity. Supervisors should not stand over workers when they are delivering the bad news, nor should they humiliate terminated employees by escorting them out the door, unless there is a real threat of violence or sabotage.

"People have long memories when they feel they've been wronged," said A. Kevin Troutman, an employment lawyer who represents management clients at Fisher & Phillips in Houston.

Although infrequent, workplace shootings by angry employees or former employees tend to gain media attention. They are often framed as a symptom of a modern economy in which workers seem disposable to companies slashing jobs or shipping them overseas to satisfy investors, workplace specialists said.

Most killings in the workplace, however, are not perpetrated by former or current employees, according to the Labor Department. Of the 409 workplace homicides in 2014, only 15 percent of the victims were killed by co-workers. More women, for example, are killed while at work by spouses, domestic partners and relatives. Men are most often killed in robberies while working as convenience-store clerks, taxi drivers and other jobs in which they handle cash.

The FBI found that the number of "active shooter" incidents - when individuals are trying to kill others in a crowded settings - are indeed rising. Between 2000 and 2006, there was an average of 6.4 such incidents each year, according to the FBI. During the next seven years, it jumped to an average of 16.4 each year.

The 160 shootings in the 14-year period killed 486 people and wounded 557, according to the FBI. Nearly half of the time, the shootings occurred in offices and shopping malls. About a quarter of the time, they happened in schools, including universities. About one in 10 occurred on government property.

The number of deaths appear to be higher in the United States than the rest of the world, said W. Barry Nixon, executive director of the National Institute for the Prevention of Workplace Violence in suburban Atlanta. But it's hard to say exactly why, he added.

It could be because the United States has more sophisticated methods of reporting workplace killings. It also could be that it's easier to get guns here than in other developed nations.

Warning signs are there

But the question of guns cuts both ways, Nixon added. One small insurance company in Georgia, for example, requires all employees to have a gun. The company's view: If everyone has a gun, everyone will be safer.

These days, more companies are training their employees about what to do if a shooter comes into the workplace. A six-minute video produced by the City of Houston, called "Run. Hide. Fight." is available on YouTube and has been viewed 4.7 million times.

Harris Garcia, director of public safety for Houston Methodist hospital, shows the video each week during new-employee orientation sessions.

After a rash of workplace shootings, including one in late 2014 at Ben Taub Hospital in Houston, where a pharmacy technician killed his co-worker before killing himself, Garcia began incorporating workplace violence prevention as part of the new employee training program.

He teaches new employees how to spot warning signs of workplace violence, from aggressive eye rolling to talking incessantly about weapons to thinly veiled threats. He also emphasizes the duty of employees to report their concerns to supervisors or human resources.

So far, 3,200 of the hospital's 20,000 employees have received the training, Garcia said.

It has been a year since he launched the training. He said he will survey employees on whether they feel better able to recognize signs of impending conflict and whether they feel comfortable reporting it. He hopes so. He also hopes they don't have much occasion to make such reports.

In his job, he said, "boring is good."