As told to THINK editor Meredith Bennett-Smith, edited and condensed for clarity.

Let’s be clear here, this is domestic terrorism. These mail bombs were designed to put someone’s life in danger with the intent to coerce the civilian population or influence the policy of government. That is the definition of a domestic terrorist — if it was sent from overseas, or was sent by someone inspired by foreign terrorists, then it would fit the definition of international terrorism. (But of course, sending bombs and creating bombs violates many other statutes besides terrorism. Once caught, prosecutors will have many options and many ways to charge the individual or individuals responsible.)

During my decades with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), I handled a lot of violent crime. I was a bomb investigator. I was a hostage negotiator. And I learned to investigate and recognize patterns in behavior, as did my colleagues.

Mail bombs have long been used to create a feeling of fear and uncertainty. I worked on the team that apprehended the D.C. sniper, and the feeling at that time was similar. Everyone in the Washington D.C. area felt like it could have been them. There’s this feeling of: It could happen to me. There’s a feeling of being watched. Someone in a basement somewhere, with evil motives, is able to reach out and touch me from afar, without ever leaving his basement. It’s a terrible feeling.

You don't send two bombs to scare somebody. You send two bombs to try to kill somebody.

But what we know about the bomber or bombers in this case indicates they are not simply intending to scare people. Bombers do not put shrapnel inside a bomb to scare somebody — because it's not visible that way. Bombers who just intend to scare their targets, or the public, tape the shrapnel to the outside of the bomb so that it adds to the fear factor.

In addition, law enforcement sources now say two bombs were sent to Rep. Maxine Waters and two were sent to former Vice President Joe Biden in Delaware. You don't send two bombs to scare somebody. You send two bombs to try to kill somebody.

We don’t know the motivations in this case, but the public should feel confident that law enforcement around the country are already working to uncover them. The behavioral analysis unit at the FBI in Quantico has included two ATF agents for decades, working to profile bombers and arsonists. I’ve used them many times. I used to supervise those profilers when I was in the explosive division. And they're very helpful.

But it’s likely that this psychological picture will be slower to develop. More immediate will be the forensic analysis, the search for clues and camera footage and the many other leads that will help identify suspects. Because this is an ongoing investigation — there could still be bombs out there. Maybe the bomber still has devices he or she hasn’t mailed yet, or maybe some devices are still in transit or stuck in mailrooms. Mail handlers in the Postal Service and UPS and FedEx have all been alerted by law enforcement and will be on the lookout now.

Unlike a mass shooter — who runs into a place, shoots everybody up, and then shoots himself in the head — mail bombers want to get away. Indeed the bomber, by the nature of the crime, has automatically distanced him or herself from the victim. So the bomber can be in a state far away, actually in another nation, when the bomb detonates. This distance gives the bombers insularity. It gives them another layer of protection. Likely they want to continue their bombing campaign, and they want to get away it.

And unfortunately it’s not particularly difficult to create a basic pipe bomb. The recipes are on the internet.

But the other thing about mail bombs is that they are not new, and law enforcement has had a lot of practice dealing with them. Some people get away with it, but most people do not. Because once you send a bomb, every federal agent in a thousand miles is going to be working on the case. We all come out of the woodwork.

This Image obtained by CNN shows a suspected explosive device received at the CNN bureau in New York City on October 24, 2018. AFP - Getty Images

Every single ATF agent is trained in bomb investigation and putting blown-up bombs back together. The FBI has a team, the postal inspectors have a team and so do the police. Everybody is all over it because it impacts all of society when a bomb goes off. And that’s why so many of these people are caught.

The key here is to be alert but not alarmed. It's okay to be fearful, but turn that energy into something productive. And adopt safe practices for your home and family, especially if you are a person who is well known. Every person who was targeted by this bomber, or would-be bomber, is a person who is prominently in the public eye. So that’s a place to start.