Sikich, a professional services firm in Naperville, Ill., used Hillard Heintze for risk assessments of its workplaces. (Taylor Glascock/For The Washington Post)

When a city worker opened fire in a Virginia Beach government office on Friday, killing 11 fellow employees and a contractor, he added another tragedy to the list of horrors recounted by Matt Doherty.

The former Secret Service agent, who trains office workers on preventing such shootings, had stood at the front of a Chicago conference room just weeks earlier and tallied similar rampages: Seventeen students and staffers massacred at a high school in Parkland, Fla. Twelve people gunned down at the Washington Navy Yard. Five staff members fatally shot at the Capital Gazette newspaper in Annapolis.

And only two months earlier, five people killed in a warehouse in Aurora, Ill., not far from where Doherty stood.

Each tragedy was preceded by red flags, alarming behaviors and threats of violence from those accused of opening fire, Doherty told a group of office workers in a Chicago high-rise. In Aurora, the shooter had told a co-worker that he would kill people if he were fired, according to a prosecutor. Later the same day, he did just that.

“That’s what we’re trying to avoid here,” said Doherty, “those warning signs.”

Doherty is trying to change the way companies think about active-shooter training. His sessions focus not on what to do if someone opens fire but how to prevent a shooting in the first place.

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While active-shooter training has become a standard security measure in schools, offices and houses of worship, Doherty’s work is part of an effort to teach employees how to flag possible threats and spot warning signs in their co-workers before violence occurs.

“Workplace violence doesn’t happen at random or out of the blue,” said Brian Harrell, the Department of Homeland Security’s assistant director for infrastructure security. “Perpetrators typically display some sort of behaviors of concern. And awareness of these indicators . . . is critical to any prevention program.”

So companies are turning to people like Doherty, who used to run the Secret Service’s Threat Assessment Center and now works at the Chicago-based security risk management firm Hillard Heintze.

He teaches employees how to watch for the missed and mishandled warning signs that have preceded some mass shootings: co-workers who seem particularly angry, who make threatening remarks or who react inappropriately to normal workplace situations.

If an employee thinks something is “off” with a colleague, Doherty said, the person with the suspicion is probably right. He promotes a variation on the post-9/11 vigilance motto: “Sense something, say something.”

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Workplaces have been common targets for shooters. An FBI study examining 160 shooting attacks between 2000 and 2013 found that nearly half of those occurred at businesses — including offices, warehouses, malls, restaurants, movie theaters, bars, supermarkets and distribution centers.

While some locations were attacked by nonemployees, others involved current or former employees or people who had relationships with workers.

“That rank-and-file employee, the administrative assistant or that low-level manager, is now cognizant of threats and violence and a potential crisis episode,” Harrell said. “They’re actively seeking the knowledge of what to do.”

Doherty advises companies to provide ways for employees to report concerns anonymously and to put policies in place for handling such issues internally when possible, including meeting with employees and turning to their own security staffs and others. When situations escalate, businesses can enlist firms such as Hillard Heintze to interview employees of concern or review their social media activities to develop risk assessments.

The idea is not to get people in trouble, Doherty said, but to sound the alarm well before a crisis.

“Not every single case is the next shooter,” Doherty, 60, told the partners and managers at the Chicago-based consulting firm Sikich during a recent training session. “That’s not what this exercise is about. It’s early intervention.”

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Research has shown that shooters frequently alarm people in their lives before their violent rampages, that their actions are often fueled by grievances, and that they target specific places and express a desire to carry out violent acts.

“When it comes to attackers, they pick their victims,” said Erroll Southers, a former FBI agent now a security consultant and a professor of national and homeland security at the University of Southern California.

The shooting in Aurora seemed to fit these patterns. The gunman showed up at the Henry Pratt Co. facility on Feb. 15, telling co-workers he was worried about being fired because of a safety violation the previous day, according to a report on the shooting released by the Kane County state’s attorney in late April.

He told one person, “If I get fired, I’m going to kill every motherf----- in here” and “blow police up,” the report said.

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The co-worker did not report the statement, because the attacker had a habit of “making ‘off the wall’ statements,” the report said.

According to the report, the attacker — Gary Martin, 45 — started shooting shortly after being told the company “would begin the termination process.” He killed four people in the meeting, including a 21-year-old intern on his first day, and injured the fifth person present, the report said. Then, the report says, he “specifically targeted” and killed another co-worker he had run into earlier in the day, when “words were exchanged” about the safety incident.

When police showed up, the attacker wounded five of them as well. He was struck multiple times during a shootout and killed.

Mueller Water Products, the parent company of Henry Pratt, did not respond to interview requests for this story.

Standing in the Sikich conference room in Chicago the day after the prosecutor’s report had been publicly released, Doherty returned to the Aurora shooting again and again, laying out some of those red flags and stressing the need for employees to report concerning behaviors.

An affable Philadelphia native, Doherty was a U.S. Capitol police officer before spending two decades in the Secret Service. He retired in 2006 and, two years later, joined Hillard Heintze, which has worked with businesses, police departments and wealthy individuals in areas including active-shooter training, private security and background investigations.

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Arnette Heintze, the firm’s co-founder and chief executive, was also a Secret Service agent and worked on details for Presidents George H.W. Bush and Bill Clinton. That experience provides a “unique skill set” in sizing up a potential threat, Heintze said.

“The goal of our training is to bring an awareness to companies and to individuals,” he said. “We’re not trying to make threat experts out of anybody in a day or two of training. But out of that training, we hope to better equip a representative of a company with the ability to go, ‘Here’s a problem.’ ”

'The end of innocence'

Companies have started paying significantly more attention to workplace violence during the past decade, said Johnny C. Taylor Jr., president and chief executive of the Society for Human Resource Management. Training that focuses on preventing such violence and responding to it is more common and is increasingly expected by employees, he said.

“It’s the end of innocence,” Taylor said. “You’re in some ways watching all of your fellow colleagues and looking for that thing that gives you an indication that this person might be a perpetrator of workplace violence.”

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To determine a person’s risk level, firms such as Hillard Heintze might evaluate the employee in a voluntary interview, said Mark Brenzinger, a clinical and forensic psychologist who, like Doherty, is a vice president of the firm. If he can’t speak to the person directly, the firm will review complaints, incident reports, social media postings and other records.

When he interviews a person, Brenzinger said, he tells them their possible risk status and asks whether they would accept treatment or counseling. But he does not make predictions about what a person will do.

“There’s always free will,” said Brenzinger, 48. “Low-risk people can go on to commit a homicide, and high-risk people can go on to do nothing.”

The goal isn’t to say whether Bob might shoot up the office, Brenzinger said. “The goal is to help Bob get better.”

The threat assessment process shouldn’t be used to cause problems for a colleague that someone simply does not like, Doherty added. Rather, the training aims to make employees active participants in the safety of their workplaces.

“We don’t just look at it from the standpoint of, ‘Look everybody, here’s a memo. There will be this evacuation drill tomorrow. We want everyone to participate,’ ” said Christopher Geier, Sikich’s chief executive and a former Phoenix police officer. “This was more inclusive to include the simple things like, ‘I heard somebody talking about something with guns that sounded a little aggressive. What do I do about that?’ ”

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There are other things employees can do to minimize the threat of violence in their offices, Doherty said. For instance, if a worker has sought a protective order against someone, such as a former romantic partner, the employee should tell the company so that it can alter its security protocols. That can include moving a person’s parking spot closer to the door or alerting security about the order and the person on the other end of it.

“I tell people the odds of it happening are one in a million,” Geier said of experiencing a workplace shooting. “But you don’t want to be the one.”