12 Ways to Spot a Potentially Violent Person in the Workplace What happened in Roanoke wasn't the first tragedy and won't be the last.

How many times have you read about a workplace shooting, and the employees said something like, "I'm not surprised he did this," or, "He always gave me the creeps, but I never thought he'd actually kill anybody"?

Related: 7 Steps to Keep Employees Safe In The Workplace

Workplace violence will never disappear, as illustrated all too frighteningly by this week's on-air shootings in Roanoke, Virginia. That's why people have to be educated. Remember the Washington Navy Yard shootings two years ago next month? I'm a security executive who appeared on CNBC at the time to discuss that incident as well as the prevention of future ones.

As I said at the time -- and still do -- unfortunately there's no magic pill, no super-technology to prevent violence on the job.

I remember how the CNBC anchor for that interview asked why the NSA, or other high-tech agency, could pick up people's online chattering but not prevent workplace shootings?

Well, not to be snarky, but . . . just how can technology predict that Joe Schmo, having eaten his breakfast of corn puffs and bacon, will then arrive at his former employer's company, walk into his former boss's office and whip out a big steak knife before slicing up his boss?

Even that scenario assumes that the company doesn't have a metal detector. Joe won't be get past security if his former boss works at the county courthouse. But what if his place of former employment is Walmart? You could walk in there with a gun anytime and nobody would ever know it.

Nevertheless, completely ignoring the issue isn't the answer. Experts on workplace violence offer a psychological profile of the typical perpetrator, and it's worth the while of businesses to know the signs:

1. A controlling nature

This person is not the industrious take-charge type, but a true freak when it comes to controlling others. Change unravels this type of person.

2. Obsession with power

This point has some overlap with number one, but the perpetrator will go as far perhaps as having a gun collection, or a subscription to some kind of ammo or paramilitary magazine or online community. He or she might also be obsessed with law enforcement.

Related: Taking the Bite Out of a Workplace Crisis

3. Violent opinions

These people tend to blame victims and revel in news about the latest school or workplace shooting, bombing, etc.

4. The inability to get along with others

This person is often rude and uncaring and blames his or her problems on coworkers.

5. An assumption that others are out to get them.

It's one thing to accuse several coworkers of gossiping about you or stealing your stapler, but true paranoiacs will believe that coworkers are poisoning their coffee, tapping their phone to listen in on conversations, etc. They might even believe that coworkers are following them around on the weekends.

6. A tendency to sue

This type of person is constantly filing lawsuits or formal grievances against not only coworkers, but neighbors and others not related to work.

7. A tendency to play the victim

These people have a blame-the-victim mindset, but then play the victim themselves by never taking credit for the bad things that happen to them; it's always the result of "someone else's" stupidity. Even a ticket for blowing through a red light isn't their fault.

8. Frequent use of malicious references

They like to say things like "She had it coming," or, "Karma is a great thing and will come back to bite him in his ass."

9. Ongoing anger

These people seem to be always seething about something. But it's everyone else's fault that their blood pressure is always high.

10. A lifestyle that is anything but health-conscious

These people often smoke and/or drink, rely on pain pills all the time, are hooked on sleeping pills, eat junk all the time and are the last people you'll see at the gym performing heavy deadlifts or taking a high-impact aerobics class.

11. A weird personality

They're the oddballs, the ones who stand out. They don't get invited to parties coworkers throw.

12. A work history of having been recently fired or laid off.

Losing a job can send someone over the deep end for several reasons: loss of income, the fact that they defined themselves by their jobs. That loss can trigger a homicidal rage.

Keep in mind that a person who doesn't exhibit most of these traits isn't necessarily immune to bringing a gun to work and shooting people. However, more times than not, a violent person shows most of the aforementioned traits. Employers need to know these traits, though some of them are obvious, like not fitting in or having a drug addiction.

In the end, workplace violence can't be prevented with a steel wall, security cards and guards, metal detectors or video surveillance. Even the violent individual unable to access the company building can easily wait in the parking lot to ambush an intended victim, or spray bullets at workers exiting the premises for lunch.

So, trust your gut if you feel that a person is potentially dangerous. Too many people are afraid of hurting someone's feelings by speaking up. But if someone's antisocial behavior and vindictive comments have you concerned, chances are this person may not be as sensitive as you think.

So, speak out if you ever find the hairs standing up on the back of your neck.

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