A security company which sells AI weapons scanners to schools is facing scrutiny after its $3.7m system reportedly failed to detect a knife used in a stabbing of a student.
Evolv Technology is aiming to replace traditional metal scanners with AI weapons scanners, which are designed to detect knives, bombs and guns.
But on Halloween last year, a student was able to enter Proctor High School in Utica, New York, with a knife - despite the school having the multi-million system in place.
Ehni Ler Htoo was walking down the corridor of Proctor High School when another student walked up behind him with a knife.
Speaking to the BBC, the 18-year-old victim's lawyer said he suffered multiple stab wounds to his head, neck, face, shoulder, back and hand.
On October 31, CCTV footage captured the perpetrator entering the school and passing through the Evolv weapons scanners, according to a source who had seen the footage.
The AI scanner is designed to alert when any kind of weapon such as firearms, knives and explosive devices are detected.
A BBC investigation found that testing revealed the system could not reliably detect large knives, with the scanner missing 42 per cent of large knives in 24 walk-throughs.
The knife used in the Utica stabbing was more than nine inches (22.8cm) long.
Evolv Technology systems are used in major stadiums and schools across the US, as well as the Manchester Arena in the UK.
Testers who found the worrying flaw have said Evolv should inform potential clients.
Meanwhile, Evolv now says its in hundreds of US schools.
Utica Schools Board bought Evolv's AI weapons scanning system in March 2022, for 13 of its schools and had it installed over the summer holidays.
One of those schools was Proctor High School.
"When we viewed the horrific video, we all asked the same question," Superintendent of Utica Schools Brian Nolan told the BBC.
"How did the student get the knife into the school?"
After the stabbing, an internal investigation was launched by Utica's school district.
Mr Nolan said: "Through investigation it was determined the Evolv Weapon Detection System... was not designed to detect knives."
Scanners were removed from Proctor High School, with 10 metal detectors being put back in their place.
Despite the incident at Proctor High School, the 12 other schools to receive the Evolv scanners still have them operating.
Mr Nolan explained the district cannot afford to get rid of Evolv's system in the remaining schools.
Since the Halloween attack, three other knives have been found on students in other schools using the Evolv system, according to Mr Nolan.
One of those knives was seven inches long.
Another knife that had got through the scanner was a curved blade with finger holes, while a third was a pocket knife.
They were all found because they were reported to staff - not because they had been detected, Mr Nolan explained.
"The kids [with the knives] all said they walked right through the weapons detection system, we asked them about that... it truly, truly does not find knives," he said.
Following the stabbing at Proctor High School, Evolv changed some of their wording on their website. Until October last year, when the stabbing happened, the company boasted about "Weapons-Free Zones" on their website.
That wording was then removed and changed to "Our Mission: Safe Zones" before being altered again to change "safe" to "safer" with: "Our Mission: Safer Zones".
The Evolv Technology system is said to use state of the art AI technology to uncover weapons.
But critics have said not enough is known about how the system works, or how effective it is.
Evolv's CEO, Peter George, has written a blog post defending the lack of detail given about how the technology works.
"It is well understood in the security industry that sharing details of a security system or operation puts people at risk", it read.
It continued: "Marketing weapons detection security requires a delicate balance between educating stakeholders on new technology and not providing bad actors with the information they could use to do harm.
"So, while public-facing marketing materials are intentionally not specific, we communicate all aspects fo the Evolv Express system - including limitations and capabilities - with the trusted security progressionals at our customers, partners and prospects.
"We believe there should be nothing schools deciding to deploy Evolv Express don’t know about the technology before making the decision to include our systems as part of their security approach.
"That’s why our team works tirelessly to make sure they have all information necessary to determine if Express is the right weapons screening system for them.
"This is not “deceptive marketing” or “security through obscurity” as those not in the weapons detection industry might declare, but rather, a critical and proven best practice of security professionals who have the profound responsibility of keeping the public safe from harm."
