AI weapon scanner fails in school knife attack, raising security concerns

A security company that provides schools with artificial intelligence (AI) powered weapon scanners is under scrutiny after a student was attacked with a knife that the US$3.7 million system failed to detect.

Last Halloween, 18 year old Ehni Ler Htoo was stabbed multiple times by a fellow student at Proctor High School in Utica, New York, despite the school having installed a weapons detection system from Evolv Technology.

Evolv Technology aims to replace traditional metal detectors with AI weapon scanners that utilise advanced sensor technology and AI to detect concealed weapons. The company claimed that its system is highly accurate and can help create “weapons-free zones.” However, a BBC investigation last year found that the system could not reliably detect large knives, missing 42% of them in 24 walk-throughs.

Despite these findings, Evolv Technology expanded into schools and now claims to be in hundreds of them across the United States. In March 2022, the Utica Schools Board purchased Evolv’s weapons scanning system for 13 schools, and the system was installed during the summer holidays.

On October 31, the attacker was captured on CCTV entering Proctor High School and passing through the Evolv weapons scanners. Brian Nolan, Superintendent of Utica Schools, said…

“When we viewed the horrific video, we all asked the same question. How did the student get the knife into the school?”

The knife used in the stabbing was over 9 inches (22.8 centimetres) long. The attack prompted an internal investigation by Utica’s school district, which concluded that the Evolv Weapon Detection System was not designed to detect knives. The scanners were removed from Proctor High School and replaced with 10 metal detectors, but they remain in operation in the district’s other 12 schools.

Since the attack, three other knives have been discovered on students in other schools within the district where Evolv systems continue to operate. These knives were found due to being reported to staff, not because the weapon scanner detected them.

Following the stabbing, Evolv’s website changed its wording from “Weapons-Free Zones” to “Safe Zones” and then to “Safer Zones.” Critics argue that not enough is known about the effectiveness of the system in detecting different types of weapons.

Evolv has not responded to questions about the Utica incident, the system’s capabilities, and its suitability for use in schools. However, in a blog post, CEO Peter George defended the lack of detail in marketing materials, stating that it is necessary to strike a balance between educating stakeholders and not providing information that could be used for harm.

Conor Healy of IPVM, a firm that analyses security equipment, accuses Evolv of exaggerating the system’s effectiveness. He said…

“There’s an epidemic of schools buying new technology based on audacious marketing claims, then finding out it has hidden flaws, often millions of dollars later. Evolv is one of the worst offenders.”