WASHINGTON - Parkland, Florida, is commemorating the second anniversary of the mass shootings at Marjory Stoneman Douglas High School that left 17 people dead and became etched in the national consciousness as a searing example of how a gunman can destroy so many young lives.

Fourteen students and three staff members were killed on Valentine’s Day 2018 and another 17 people were wounded. The alleged shooter, a former student of the high school, is awaiting trial and is possibly facing the death penalty.

Parkland Commemorates Second Anniversary of High School Mass Shooting

In the immediate aftermath of the shooting, many hoped it would mark the beginning of the end of such massacres, especially at schools. However, since that attack, there have been many more high profile mass shootings in the United States, including an attack three months later at Santa Fe High School in the Houston, Texas, metropolitan area that left 10 people dead, including eight students.

Parkland Commemorates Second Anniversary of High School Mass Shooting

Thirteen mass shootings have taken place in the two years since Parkland, including massacres at the Capitol Gazette newspaper office in Annapolis, Maryland, the Tree of Life synagogue in Pittsburgh, Pennsylvania, a nightclub in Thousand Oaks, California, and a Walmart in El Paso, Texas.

Parkland Commemorates Second Anniversary of High School Mass Shooting

Since the shooting in Parkland, survivors of that attack have ushered in a wave of student activism, organizing a series of rallies, school walkouts and voter registration drives, calling for stricter gun laws in the United States.

The Giffords Law Center to Prevent Gun Violence reported in its 2019 year-end review of local gun laws that 137 gun safety bills have been signed into law in 32 states and the District of Columbia since the Parkland shootings.

At the national level, however, there remains wide disagreement among politicians over how best to stop gun violence. Many on the political left argue for stricter gun laws, while politicians on the right call for increased security measures as well as mental health treatment to stop potential shooters before they carry out their crimes.

The majority-Democratic House of Representatives passed bills in February 2019 requiring universal background checks on all firearm sales and giving the FBI more time to do background checks on gun purchases. But the legislation has stalled in the Republican-controlled Senate.

In an attempt to provide politicians, academics and the public with more information on mass shootings, The Violence Project, a nonpartisan think tank, built a groundbreaking database on mass shooters. , closely examines the background and motivation of mass shooters themselves in an effort to understand why these crimes are being committed.

Researcher James Densley, Ph.D., who built the database along with Jillian Peterson, Ph.D., told VOA they started the project because they were becoming increasingly frustrated by the same either-or theories that mass shootings were caused by guns or mental illness.

“We just felt like there has got to be a better way to have these conversations and to be more informed by the evidence,” Densley said.

The database covers every mass shooting that has taken place in the United States between 1966 and 2019.

Since 1966, there have been 167 mass shootings in the country, defined by the Congressional Research Service as “a multiple homicide incident in which four or more victims are murdered with firearms — not including the offender(s) — within one event, and at least some of the murders occurred in a public location.” Murders that involve any other underlying criminal activity, including gang violence or armed robbery, or are solely categorized as domestic violence, are not included.

According to The Violence Project, nearly all mass shooters have four things in common: early childhood trauma and exposure to violence at a young age; an identifiable grievance or crisis point; validation for their beliefs, in part by studying past shootings to find inspiration; and the means to carry out an attack.

In compiling the data, the Violence Project found that while there is no single profile of a mass shooter, it is easier to see patterns in shooters when looked at them from the point of view of where they carry out their crime.

For example, in workplace shootings, the gunman tends to be a male in his 40s, can be of any race, and is an employee of a blue-collar business where he is having trouble at work. He tends to use handguns and assault rifles that he legally owns. By contrast, mass shooters who kill in a K-12 school tend to be a suicidal white male student of the school with a history of trauma. He leaks his premeditated plan before the shooting, and uses multiple guns stolen from a family member.