Good morning, Bulletin readers. Ahead of the 20th anniversary of Columbine, the school’s former principal reflects on healing after violence. The NRA’s financial crunch has now led to a public spat with its biggest outside partner. And new statistics show the risk domestic shootings pose to teen girls.

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WHAT TO KNOW TODAY

NEW from THE TRACE: He was the principal at Columbine High School. Helping communities heal became his life’s work. Frank DeAngelis heads up a national support network for other principals who’ve experienced shootings. Ahead of the Columbine shooting’s 20th anniversary, DeAngelis spoke with The Trace’s Elizabeth Van Brocklin about helping others find their footing after experiencing the worst. “If you had asked me 20 years ago if we would still be talking about Columbine, I’d say no way,” he said. “But we also represent hope and endurance.”

The NRA is suing its longterm advertising partner. Ackerman McQueen racked up $42.6 million in billings to the gun group in 2017, according to tax filings. In a highly unusual move, the National Rifle Association is now taking the firm to court to demand documents supporting those charges. Ackerman calls the suit “frivolous” and says it turned over “every single thing” requested by the NRA’s auditors. The Wall Street Journal has the story, which provides the latest evidence that the NRA’s financial troubles are sowing divisions within its leadership. From The Trace archives: The high-priced attorney handling the NRA’s lawsuit is the son-in-law of one of Ackerman McQueen’s founders.

Nearly 7 percent of murdered teens were killed by a current or former dating partner. That’s according to a new study in JAMA Pediatrics analyzing domestic partner violence among teens in 32 states between 2013 and 2016. Researchers found that the victims were largely women and girls, that guns were the most common weapon used, and that the murders were often spurred by breakups or jealousy.

The long-term health consequences of mass shootings are under-researched. In a commentary piece, public health researchers cited the suicides of two Parkland survivors and a Sandy Hook parent as evidence of the long-term psychological and emotional toll caused by gun violence. The authors cite several promising strategies that they say deserve more in-depth study, including population-based health care models that anticipate the needs of a community and proactively offering services to survivors.

Rival gangs came together in Denver amid rising city homicides. People who had shot each other were among hundreds gathered at a public park on Sunday for a “Heal the Hood” barbecue hosted by a local community center. Last year, Denver saw the highest number of murders in over a decade. “If we all come together,” said the event’s organizer, “then we will be able to solve some of the problems, be able to stop some of the gang violence, be able to stop some of the senseless killings.”

A Pennsylvania mayor faces charges for allegedly pointing a gun at a group of teens. Mayor Kevin M. Gross of the town of Derry, 45 miles east of Pittsburgh, reportedly drew his weapon at a local park on Sunday night and aimed it at a group of young people between the ages of 12 and 15. Police said the incident happened after a fight between two of the teens and the mayor’s son.

Young children across the United States were victims of gun violence over the weekend. In Arizona, on Thursday night, a man killed his wife and two of his children, ages 5 and 7. Police found his 3-year-old daughter hiding under the bed, with no physical injuries. The next day, a 7-year-old girl was watching television when someone opened fire on her Georgia home, hitting her. Her foster mother says she is fighting for her life. In Alabama, a baby girl was injured and her father was killed on Saturday after the man unintentionally fired a gun during a diaper change outside a Chuck E. Cheese. And on Sunday night in New Hampshire, a 2-year-old girl was injured while sleeping when a bullet flew through the ceiling of the downstairs apartment. The man who fired the shot is facing felony charges. Gun violence has a devastating impact on American children. Our Since Parkland project profiled 1,200 young people killed by guns in the year following the Parkland shooting, not including suicides.

ONE LAST THING

The gun industry has failed to embrace smart guns despite signs of consumer interest. Why? Nearly half of gun owners in the United States would consider buying a gun equipped with technology that prevents it from being fired by an unauthorized user, according to a Johns Hopkins University study. But as Bloomberg Businessweek documents in a new feature, the potentially life-saving technology has run into significant headwinds. In January, The Trace’s Brian Freskos reported on a new generation of entrepreneurs who are turning out smart guns and accessories that address nagging reliability concerns, but still face obstacles to getting their products onto shelves. “The consistent statement from manufacturers has been, ‘We think it’s good, we like it, but we don’t want to be first,’” the co-founder of a Nevada-based smart-gun start-up said. “They don’t know how the market is going to cast this, and that fear, uncertainty, and doubt is a big barrier.”