A 1 a.m. shooting at a party in downtown St. Louis kills one and injures nearly a dozen. Gunmen open fire during a fight near Florida’s Hollywood Beach, injuring nine, including a 1-year-old. Bursts of gunfire at a Sweet 16 party in Dadeville kill four and wound more than 30.

What these and other recent mass shootings share in common is they all involve suspects in their teens, highlighting what can be a deadly mix of teenage bravado and impulsiveness with access to guns.

The days when many teens opted to fight out disagreements with fists seem quaint by comparison.

Here is full coverage of the Dadeville birthday party shooting

“I remember when I was a child and we had fights — somebody got a black eye or a broken nose and (they) lived to tell about it,” St. Louis Mayor Tishaura Jones told reporters after Sunday’s shooting.

Reaching for a gun is the default these days for some teens who are as quick to take offense as to pull a trigger, agreed Rodney Phillips, a 50-year-old former Chicago Black Disciples leader who works with gang members nationwide to tamp down festering beefs.

“Now, the first thing out of their mouths is, ‘I’m gonna kill you.’ It’s the brazenness of (the shootings), the reckless abandon, doing it in public places,” Phillips said. “It wasn’t like that when I came up.”

The aunt of 17-year-old Makao Moore, who died in the St. Louis shooting, said teens too often express anger with a gun.

“If we don’t figure it out, it’s going to continue to happen,” Sharonda Moore told the St. Louis Post-Dispatch.

Among the solutions to reducing teen violence, Jones said, was to keep expanding programs offering young people activities in safe spaces, including movie and music nights.

More firearms, and even more powerful firearms, have enabled teens, or anyone wielding a gun, to maim and kill more people in single incidents.

A handgun fired at the April Sweet 16 party — in a dance studio crammed with up to 60 people — had been altered to shoot more rapidly, Alabama Special Agent Jess Thornton told a court hearing.

“Witnesses said it sounded like a machine gun,” the investigator said. Afterward, 89 bullet casings littered the scene and there was “blood everywhere.”

Bullets riddled walls and shattered glass at the shooting in a fifth-floor office in St. Louis. Police released photos of two young men clutching apparent AK-style rifles. One detained suspect was 17.

In many cities, illegal guns are never too far out of reach.

In areas with high gang activity, some guns are stolen from homes, gun stores or trains. To lower the risk of being stopped by police while in possession of guns, gang members typically hide them nearby, tucking the weapons into walls and inside tire rims, he said.

Powerful firearms became more readily available starting in the 1980s, before which knives and low-caliber pistols were often the weapons of choice by teens who killed, said James Alan Fox, a professor of criminology, law and public policy at Northeastern University in Boston.

“With guns, teenagers tend to be trigger happy,” he said. “They’ll pull the trigger without fully thinking about the consequences.”

According to FBI data, around 90% of homicides in 2019 by teens 15 to 17 involved firearms, up from around 60% in 1980. Fox, though, said the rise in homicides by teens hasn’t correlated directly with the rising numbers of guns.

Just how many guns are around and available to teens is impossible to know. The Switzerland-based Small Arms Survey estimated in 2018 that there were some 390 million guns held by civilians in the U.S., more than those held by civilians in the other top 25 countries combined.

Mayor Jones said causes of the kind of violence that occurred Sunday are complex. Among the problems she highlighted was a trend of teenagers spilling into downtown St. Louis for late-night parties, with parents sometimes dropping them off.

“Downtown is not a 1 a.m. destination for your 15-year-old,” she said. “It’s not a place to drop children off unsupervised.”

Investigators in St. Louis, Alabama and Florida didn’t immediately suggest motives for the respective shootings. But indications are tensions rose suddenly in each.

Donna Rhone, whose son’s face was grazed by a bullet in the St. Louis shooting, told KTVI-TV that partygoers had been well-behaved before the shooting.

“Then immediately, that’s when everything shifted,” Rhone said, citing her son. “It goes from being so lighthearted to pure terror.”

When a music speaker fell with a bang at the Alabama party, one person lifted their shirt to display a gun, Thornton said. Shooting began after an announcement telling those with guns to leave. At least three shooting suspects were teens.

Pushing and shoving between two groups preceded the Memorial Day shooting in Florida, when members of one group pulled guns and fired at the other and at bystanders, an affidavit alleged. Among those charged: a 15-year-old, a 16-year-old and an 18-year-old.

For 2020, the first year of the pandemic, numbers of homicides by teens 12 to 17 jumped by nearly 40% compared to the previous year, from 974 to 1,336, according to FBI data. There was a total of around 18,000 homicides in the U.S. in 2020.

Homicides by teens 12 to 17 soared between 1984 and 1994, from 958 to a historic high of 2,800, according to the FBI. After falling to a low of 700 in 2013, numbers crept up, though they remain below mid-90s’ numbers.

When teens kill, their victims are often young.

The St. Louis victims were between 15 and 19. Those killed in the Alabama shooting were 17, 18, 19 and 23, while most of more than two dozen others injured ranged in age from 14 to 19.

Homicide in 2019 was the third leading cause of death for those between ages 12 and 17, behind accidents and suicide, according to the Centers for Disease Control and Prevention. Homicide is now the leading cause of death among African American youth.

Philips said social media is another factor driving teen violence. Feuds fanned in cyberspace with exchanges of insults can spill into the real world with exchanges of gunfire.

In the heat of the moment, peer pressure can contribute to a minor dispute spinning out of control. Fox said around a third of homicides by teens involve two or more people.

“Sometimes, no one individual wants to do the crime but everyone thinks everyone else wants to do it,” he said. “No one wants to be ostracized by the group.”