An artificial intelligence-powered weapon detection system failed to pick up the handgun a 17-year-old Nashville student used in a school shooting Wednesday that left a 16-year-old girl dead, officials said.

The software, called Omnilert, failed to detect the gun because of where cameras were located inside Antioch High School, Metro Nashville Public Schools spokesperson Sean Braisted said at a Thursday afternoon news conference.

But the system was activated by police brandishing their weapons during the response to the shooting, Braisted said.

Omnilert connects to the school’s existing network of cameras and uses AI technology to detect weapons, he said, but “in this instance, based on the shooter’s location in proximity to the cameras, it wasn’t close enough to get an accurate read and to activate that alarm.”

Metro Nashville Public Schools Director rienne Battle said “there is not one system that is 100% going to capture everything that a person may have on them.”

Omnilert works by turning security cameras “into life-saving tools, protecting lives while reducing the operational, legal, and social costs of gun violence,” its website states. It helps detect firearms and then triggers immediate alerts.

“These are designed to capture things that are on camera, and so we wanted to have a system that worked on multiple cameras throughout the network, it does work but it’s not going to work in every instance, in every spot based on where that weapon might be visible,” Braisted said. “So that’s why we have additional safety and security protocols.”

In addition to Omnilert, the school uses AI systems at the front door, has security vestibules and uses school resource officers.

“It all works together as a system, but one system alone is not going to keep people safe,” Braisted said. “And there’s also just the general public concerns around how a 17-year-old has a weapon.”

“I mean these are questions that are beyond the scope of Metro Schools, but need to be addressed by the broader community,” he said. “But we are doing what we can as a district to install and equip our schools with the safety protocols and resources that we can use to be safe.”

The missed detection offers a lesson in the shortcomings of high-tech security solutions — and the risk of relying on them, experts said.

“This highlights the challenges school districts face,” said Donald Maye, head of operations at IPVM, a surveillance technology research company that investigates weapon-detection systems.

“They’ll make these announcements that they’ve invested millions on a solution and then there are still many cases that can occur where the system is not going to be a factor in preventing violence.”

Amy Klinger, director of programs for the nonprofit Educator’s School Safety Network, said the most effective safeguards against violence are based on building trust among students, teachers and administrators to share early signs of potential threats — like erratic behavior or troubling social media posts.

“In the vast majority of cases there is something of concern — behaviors, disclosures, conversations, warning signs — that if someone is paying attention you could pick up on,” Klinger said. “If you combine that with technology, great. But you can’t replace it with technology.”

Some have questioned why the school did not use metal detectors. Battle told reporters Thursday that research has shown there are pros and cons of using the detectors.

“There are lots of unintended consequences, mainly when you think about the types of learning environments we want for our students. I mean, the first person we want our students to interact with are their principals and their teachers and their fellow students,” she said.

A motive in the shooting is unclear, although Nashville Police Chief John Drake said authorities are looking into “some materials on the internet” believed to be from the shooter, who was identified as Solomon Henderson. He fatally shot himself after the attack.

Authorities said Henderson was an active student at the school and took the school bus before later opening fire in the cafeteria, killing Josselin Corea Escalante. One other student was wounded when he was grazed in the arm.