First came the warning signs. Then a teen opened fire on a Nashville school.

In 2020, when he was 13, his mom called the police, saying he punched her in the face and tried to hit her with a chair after she asked him to clean up the backyard. An officer with the Clarksville Police Department charged Henderson with simple assault, according to an incident report that ProPublica and WPLN News obtained through a records request. The arrest has not been previously reported.

In 2023, Nashville police officers visited the family’s home and said they removed two guns. A Police Department spokesperson said the guns belonged to adults in the home, but the incident report could not be released because the visit involved a minor.

At Antioch High School a year later, Henderson pulled a knife on a 15-year-old girl. For that, he was charged with reckless endangerment, according to a court document the girl’s mother shared with ProPublica and WPLN. School officials responded by suspending Henderson for two days, according to WSMV-TV, which obtained a disciplinary record that refers to the weapon as a “box cutter.”

Two months after that, in December 2024, a user on X flagged one of Henderson’s accounts and tagged the FBI, encouraging the agency to look into his connections with school shooters. Henderson’s accounts, which did not use his first or last name, were suspended in December and in January for violating “rules against perpetrators of violent attacks.” In school, his grades were slipping. A teacher told WSMV that Henderson was a “walking red flag.”

On Jan. 22, Henderson came to school with a pistol. He fired 10 shots in 20 seconds in the cafeteria, killing 16-year-old Josselin Corea Escalante before he turned the gun on himself.

It’s unclear how many of Henderson’s red flags were heeded. In response to questions about Henderson’s past interactions with law enforcement, the Metropolitan Nashville Police Department declined to comment. When asked if the incident in Clarksville came up during its investigations, a spokesperson indicated the department did not know about it. And school officials declined to say whether they considered incidents from his past when determining his suspension, citing student confidentiality laws.

Henderson’s suspension for threatening another student with a weapon stands in stark contrast to other far harsher penalties students have faced under a series of recently passed state laws designed to prevent school shootings and crack down on hoax threats. A 10-year-old who points a finger gun can get kicked out of school for a year, and an 11-year-old who’s rumored to make a threat can be charged with a felony. Neither of those children, or others whose punishments ProPublica and WPLN examined last year, brought a weapon to school.

The girl Henderson threatened, Gemima, told ProPublica and WPLN that she was surprised to see him in the hallways just days after the incident. ProPublica and WPLN are using just her first name because she is a minor. “He had a whole knife in school, and he didn’t get expelled,” she said. “It just doesn’t sit right with me.”

Lawmakers say that the harsh punishments are necessary to deter students from making hoax threats that frighten students and teachers and waste time and resources to investigate. But lawyers and judges say the approach floods the justice system with cases that could be handled at school, making it harder to focus on the real dangers.

“Any time when you have an influx of cases that are threats or conversations that have to be investigated, I think it does take away valuable resources for the actual, real cases that we need it for,” said Judge Sheila Calloway of the Davidson County Juvenile Court.

State Rep. Gloria Johnson, a Democrat and former special education teacher, says Tennessee’s Republican supermajority should focus more on implementing protections that will actually help stop mass shootings rather than teaching a lesson to kids who have no intention of carrying one out.

“Every time we try to come up with something to prevent these incidences, they’re not interested,” Johnson said. “But they are interested in enhancing penalties and convicting 7-year-olds of felonies.”

Henderson had complained about the students who had gotten in trouble for making threats at his school, worried that the increased police presence would get in the way of his planning. In an online diary that he made public before the shooting, he wrote that he would never have called attention to himself like other kids were, calling them “clowns.” In order to carry out an attack, he wrote, the attacker needed the “element of surprise.”

First image: Paige Pfleger/WPLN. Second image: George Walker IV/AP Photo.

Antioch High School, first image. A parent prays as she waits for her daughter following a shooting at the school in January.

Tennessee requires school officials and police to work together on “threat assessment teams” to investigate cases where students show “dangerous or threatening behavior.” They are supposed to resolve problems before they escalate to violence and determine whether troubled students need additional resources like counseling or other mental health services.

“When you’re looking at children who might have behaviors that are concerning or other stressors going on in their lives, we want to be capturing and digging into that right away,” said Melissa Nelson, a school safety and security consultant who has trained thousands of school employees on managing threats.

School shooters usually plan their attacks in advance, federal research shows, and most act out in concerning ways well before they attack. When the process is working at its best, threat assessment teams can step in early to set students on a better path. If a kid is acting out because he is being bullied, for example, the team might switch his lunch hour to separate him from the bully or help mediate a better relationship between the students. These interventions may not have been enough to deter Henderson, but repeated contact and observation over the years he was in the district is considered best practice by experts.

Under state law, law enforcement and school districts don’t have to publicly disclose their threat assessment process or how effective it is at stopping violence. As a result, the public has little transparency into what steps are being taken to keep students like Henderson from becoming the next school shooter.

“When we aren’t using evidence-based practices and we don’t have a good framework of specific things we should be looking for,” Nelson said, “then we do have a very high potential of missing warning signs.”

Metro Nashville Public Schools declined to comment on why they gave Henderson a two-day suspension instead of a harsher punishment for pulling out a knife or whether they completed a threat assessment. But according to the district’s discipline chart, its schools are not required to complete a threat assessment for students punished for reckless endangerment, which was what Henderson was charged with in court.

If school staff and police did complete an assessment, they would have been required to consider Henderson’s history of violence and risk of acting aggressively in the future, according to a copy of a threat assessment questionnaire the district shared with ProPublica and WPLN. They also would have had to decide how to address any concerns they had about Henderson, such as monitoring his social media, randomly checking his backpack or locker and helping him to get counseling.

Henderson’s online diary lends insight to warning signs that officials may have missed. He wrote that police once found a gun at his house that belonged to him, but his dad took the blame. He also wrote that his mom had been abusing him for years, including putting a gun to his head when he was young. ProPublica and WPLN made multiple attempts to reach Henderson’s parents for comment but did not hear back.

The diary also revealed he was active in online groups that glorified mass shooters and that he promoted racist, antisemitic, anti-LGBQT+ and violent misogynistic views. He wrote that he felt lonely at school and wanted to stab his classmates to death.

The way the school district handled Henderson’s behavior has frustrated Gemima and her family. The family made the decision to not go to court in the case against Henderson — they wanted the school to get him counseling or remove him to an alternative school, and they worried about overly harsh punishment in the justice system. It’s a decision that her mom, Patricia Lerime, said she now regrets.

“I should have gone to court,” she said, pointing out that he might have been required to get help. “But I felt like Metro failed him.”

Gemima recalled that when a school administrator confronted Henderson about threatening her with a knife, he began yelling at Gemima and called her the N-word. No one told her that he would be back at school days later. On the day of the shooting, she said, it didn’t take long for information to spread among students that Henderson was the assailant. It struck her, because of her history with Henderson, that she could have been one of his victims.

“Y’all failed me, and y’all failed everybody else in the school,” Gemima said. “I just feel like the situation should have been handled differently.”

Mollie Simon of ProPublica and Phoebe Petrovic of Wisconsin Watch contributed research.