More than five years after his son was gunned down in the deadliest mass shooting in modern U.S. history, Richard Berger still asks why.

Why Stephen Berger was killed the day after celebrating his 44th birthday. Why the gunman rained bullets over the Las Vegas Strip in 2017, turning a country music festival into a bloodbath. Why the massacre’s death toll did not shock U.S. leaders into doing more to prevent that kind of violence from happening again and again.

Why?

“It’s just a hole in our hearts,” Mr. Berger said. “We just don’t know, and we just don’t know what to say.”

For the Bergers, the families of the other 59 victims in Vegas—and relatives and friends of countless others slain in mass killings across the country in the years since—these questions loom as large now as when the crimes happened. Yet the carnage continues, with 2023 starting out at a torrid pace.

Over the first five months and 27 days of this year, 131 people have died in 26 mass killings—an average of one mass killing per week.

The headlines are numbing: Eight people, including three children, shot to death at an outdoor mall in Allen, Texas. Four partygoers slain and 32 injured in small-town Alabama during a Sweet 16 birthday party that ended with a girl kneeling beside her fatally wounded brother. Six people, including three 9-year-old children, gunned down at an elementary school in Nashville.

The May 6 Allen shooting represented the 24th mass killing of the year, according to a database maintained by The Associated Press and USA Today in a partnership with Northeastern University. That is the most during the first five months of a year since data was first recorded in 2006.

The number killed is a fraction of the total number of people who died by homicide for the year. The database counts killings involving four or more fatalities, not including the perpetrator, the same standard the FBI uses, and tracks a number of variables for each.

“Nobody should be shocked,” said Fred Guttenberg, whose 14-year-old daughter, Jaime, was one of 17 people killed at a Parkland, Florida, high school in 2018. “I visit my daughter in a cemetery. Outrage doesn’t begin to describe how I feel.”

The Parkland victims are among the 2,896 people who have died in mass killings in the U.S. since 2006, according to the database.

Drumbeat of Death

Mass killing atrocities have been driven almost exclusively by gun violence, since all the incidents in 2023 involved firearms in some way. Shootings account for the vast majority of mass killings, though there are examples where the perpetrator used knives or other weapons as well.

Experts point to a few contributing factors: a general increase in all types of gun violence in recent years, the proliferation of firearms amid lax gun laws, the effects of the coronavirus pandemic including the stress of long months in quarantine, a political climate unable or unwilling to change the status quo in meaningful ways and an increased emphasis on violence in U.S. culture.

Such explanations are of little comfort not only to the families ripped apart by the killings but to Americans everywhere who are reeling from the cascading, collective trauma of mass violence.

This year’s killings have happened in different ways, from family and neighborhood disputes to school and workplace shootings to explosions of gunfire in public spaces. They have taken place in rural as well as urban settings. Sometimes people knew their killers; other times, they did not.

The Las Vegas shooter’s motive remains unknown even now. The high-stakes gambler was apparently angry over how the casinos treated him despite his high-roller status. Still, the FBI has never uncovered a definitive reason for the slaughter, which ended with more lives lost than in any single mass killing in decades.

Contributing to 2023’s steady drumbeat of death: the grisly murder-suicide in Utah that left five children, their parents and their grandmother dead just days into the new year; seven people found shot to death in rural Oklahoma after a man killed his wife, her three children and two missing teenagers; four people found shot to death in an RV in a small Mojave Desert community in California.

Yet while these tragic events garner an outsized amount of attention in the news media and the public’s mind, they represent only a tiny fraction of overall gun deaths.

Far more frequent are fatal shootings involving fewer than four people and deaths from domestic violence. And then there are the suicides, which comprise more than half of the 17,000 gun deaths so far this year, according to the Gun Violence Archive, which monitors news media and police reports to compile data.

Still, mass killings spark the deepest fear in most people’s hearts.

“People around the country all send their kids to schools—and they worry about if they send their kid to school, are they going to get shot?” said Daniel Webster, a professor at the Johns Hopkins Center for Gun Violence Solutions.

The fact is, though they are less common than other gun deaths, the mass killings keep happening—20 years after Columbine, 10 years after Sandy Hook, five years after Las Vegas and one year after massacres at a supermarket in Buffalo, New York, and an elementary school in Uvalde, Texas.

What Can Be Done?

The 2023 numbers stand out even more when they are compared with the tally for full-year totals since data was collected. The U.S. recorded 30 or fewer mass killings in more than half of the years in the database, so to be at 26 almost halfway through this year is remarkable.

The violence has erupted from coast to coast and was sparked by various motives. Murder-suicides and domestic violence, gang retaliation, school shootings and workplace vendettas. All have taken the lives of four or more people at once since January 1.

Yet barriers to change remain. The likelihood of Congress reinstating a ban on semi-automatic rifles appears far off. Last year, the Supreme Court set new standards for reviewing the nation’s gun laws, calling into question firearms restrictions nationwide.

The pace of mass shootings so far this year does not necessarily foretell a new annual record. In 2009, the bloodshed slowed and the year finished with a final count of 32 mass killings and 172 fatalities. Those figures just barely exceed the averages of 31.1 mass killings and 162 victims a year, according to an analysis of data dating back to 2006.

Gruesome records have been set within the last decade. The data shows a high of 46 mass killings in 2019 and 230 people slain in such tragedies in 2017. That year, 60 people died in the shooting referenced earlier at an outdoor country music festival on the Las Vegas Strip. The massacre still accounts for the most fatalities from a mass shooting in modern America.

“Here’s the reality: If somebody is determined to commit mass violence, they’re going to,” said Jaclyn Schildkraut, executive director of the Rockefeller Institute of Government’s Regional Gun Violence Research Consortium. “And it’s our role as society to try and put up obstacles and barriers to make that more difficult.”

But there is little indication at the state or federal level—with a handful of exceptions—that many significant policy changes are on the horizon.

Some states have tried to impose more gun control within their borders. In April, Michigan Governor Gretchen Whitmer signed a new law mandating criminal background checks to purchase rifles and shotguns, whereas the state previously required them only for people buying pistols. Later that month, Washington Governor Jay Inslee signed a law banning certain kinds of semi-automatic rifles. But it faces a federal court challenge.

Other states are experiencing a new round of pressure. In conservative Tennessee, protesters descended on the state Capitol to demand more gun regulation after the March Nashville school shooting.

At the federal level, President Joe Biden last year signed a milestone gun violence bill, toughening background checks for the youngest gun buyers, keeping firearms from more domestic violence offenders and helping states use red flag laws that enable police to ask courts to take guns from people who show signs they could turn violent.

What Can We Expect?

Despite the blaring headlines, mass killings are statistically rare, perpetrated by just a handful of people each year in a country of nearly 335 million. And there is no way to predict whether this year’s events will continue at this rate.

Sometimes mass killings happen back-to-back—like in January, when deadly events in California occurred just two days apart—while other months pass without bloodshed.

“We shouldn’t necessarily expect that this—one mass killing every less than seven days—will continue,” said Northeastern University criminologist James Alan Fox, who oversees the database. “Hopefully it won’t.”

Still, experts and advocates decry the proliferation of guns in the U.S. in recent years, including record sales during the first year of the COVID-19 pandemic.

“We have to know that this isn’t the way to live,” said John Feinblatt, president of Everytown for Gun Safety. “We don’t have to live this way. And we cannot live in a country with an agenda of guns everywhere, every place and every time.”

Jaime Guttenberg would be 19 years old now. Her father now spends his days as a gun control activist.

“America shouldn’t be surprised by where we are today,” Mr. Guttenberg said. “It’s all in the numbers. The numbers don’t lie.”

Can We Know Why?

Even people who study mass killings are perplexed by the sustained pace of the brutality.

“We have plenty of examples of things that seem to be at the breaking point in this country,” said Katherine Schweit, a former FBI executive who created the agency’s active shooter protocol after Sandy Hook. “When I was asked to work on this in 2013, I didn’t ever imagine 10 years later I’d still be working on the same thing.”

It will take years—if even possible—for researchers to pinpoint what’s behind the drastic increase in gun violence. Advocates say some measures could perhaps avert such crimes—firearms reform and weapons bans among them—but note there is little appetite on Capitol Hill to implement them.

“I think the United States has a relationship with guns unlike any other country in the world,” said Kelly Drane, research director for the Giffords Law Center to Prevent Gun Violence. “These events are a consequence of our failure to put in place prevention measures.”

For now, any legislative efforts by Washington, D.C., and individual states have done little to slow the pace of violence or alleviate the nation’s pain, further exacerbated by the pandemic and a rapidly growing political and cultural divide.

“These tragedies compounded one after the other, making it almost too much to bear,” said Roxanne Cohen Silver, a psychology professor at the University of California, Irvine, who studies coping with traumatic life events.

The mass killings, Ms. Silver noted, “are just another tragedy on top of all of these other psychological and emotional challenges.”

Stephen Berger’s father, Richard, is now 80. He spends his days with his grandchildren—one is a soccer goalie who reminds him of Steve, who had a passion for basketball. Their family awards annual athletic scholarships at Stephen’s high school.

Mr. Berger watches the teenagers as they approach the next phase of their young lives, flush with promise and full of life. But his son is dead, and five years later, he is still left wondering: Why?

For the Bible answer to this question, read Why Man Cannot Solve His Problems.

This article contains information from The Associated Press.