Every potential mass shooter is different, but prospective killers often exhibit the same pre-attack behaviors, and their actions can be monitored to help prevent future murders, FBI special agent Karie Gibson told a conference of security and law enforcement officials at Northeastern on Wednesday.

Many prospective shooters can be depressed and withdrawn,  preoccupied with mass murder, and have a keen interest in acquiring firearms and tactical gear, said Gibson, who studies the characteristics of mass shooters at the FBI Behavioral Analysis Unit. Most of them are “brittle people,” lacking the social ties to deal with stress in a non-violent way.

“A paper cut for us,” she said, “is like a stab in the heart for them.”

Gibson, who works with state, local, and federal partners to prevent targeted violence, delivered one of 12 presentations at the inaugural Campus Safety and Security Summit, organized by the Department of Homeland Security and held at Raytheon Amphitheater.

The two-day event featured talks on such security and emergency response issues as hate crimes on college campuses,  how to report suspicious activity, and “swarm leadership,” which is what happens when people spontaneously pitch in to help victims of a calamity. Presenters included officials from Crime Stoppers USA, the Nationwide Suspicious Activity Reporting Initiative, and the National Center for Campus Public Safety.

“Campus security organizations in some cases are larger than municipal police departments and their challenges are often unique,” said Wesley Moy, chief of partner engagement at the Department of Homeland Security. “We wanted to get peers together with the objective of sharing best practices.”

Gibson summarized the six steps on the “pathway to violence,” a common phrase in discussions of the evolution of homicidal acts. The first step is the grievance, she said, a “slight or humiliation” that the potential perpetrator “can’t move past.” Other steps include planning, preparation, and implementation.

“The hard part is trying to find mass shooters before they actually come on premise with a firearm,” she said. “We have to foster culture where people feel comfortable coming forward to share this information.”

Many prospective mass shooters fantasize about killing, she said, and leak their plans to others. They create “legacy tokens” in the form of letters and videos to claim responsibility for their crimes and enhance their notoriety. Some change their appearance, coloring their hair or shaving their head, while others abruptly stop using alcohol and drugs in preparation for their attack.

“They want to experience their attack in full form,” she said. “They don’t want to be numb.”

Gibson said she reviews the behaviors of potential mass shooters, evaluating their work, school, and medical records, conducts a threat assessment, and then engages with law enforcement agencies to develop threat management strategies to mitigate risk.

“You can’t predict there will be a school shooting today, but can prevent these attacks from happening,” she said. “Waiting to act until someone makes a threat is not ideal, as some people who pose the most concern may never make one.”