A Nashville school district invested about $1 million in AI gun identification software, the school district said, leaving some to wonder what went wrong in detecting a school shooter in the halls.

More than a week ago, 17-year-old Solomon Henderson carried out a shooting inside Antioch High School in suburban Nashville, killing a classmate and wounding another. Henderson died after turning the gun on himself, police said.

The gun detection system at the school failed to detect Henderson’s weapon during the January 22 shooting