Earlier this year, New York City started testing a gun detection system from Evolv Technologies at City Hall and Jacobi Medical Center in the Bronx. Mayor Eric Adams, who has said he came across the system on the internet, has been talking up the tech for months as a way to help combat gun violence. Now, it has emerged that two people who donated $1 million to support Adams’ mayoral run work at companies with investments in Evolv, as the New York Daily News first reported.

The CEO of the investment firm Citadel, Kenneth Griffin, last year donated $750,000 to Strong Leadership NYC, a political action committee (PAC) that supported Adams. Jane Street Financial Services founder Robert Granieri gave $250,000, according to records.

As of May 16th, Citadel held 12,975 shares in Evolv, a publicly traded company. It holds another 89,900 for other investors as call options. Jane Street held 76,570 shares as of May 17th. The stock held by all shareholders totals 143.4 million, so both firms own a relatively small chunk of Evolv.

A spokesperson for Adams told the Daily News that the mayor didn’t recognize the names of Griffin and Granieri and wasn’t sure whether he’d met with them. The spokesperson said that before a pilot of Evolv’s system started at Jacobi Medical Center in February, the tech was being used at other city hospitals.

NYC has considered using the AI weapon detection technology in transit systems, particularly following a mass shooting on a subway train in Brooklyn last month. As Fast Company notes, Evolv charges between $2,000 and $3,000 per scanner per month for a subscription. Installing one at every subway entrance and paying staff to operate them would cost hundreds of millions of dollars per year. Given the costs, it’s unlikely that the scanners would be ubiquitous. 

The effectiveness of Evolv’s system has been brought into question too. While the company has not publicly disclosed its false positive rates, it has acknowledged the issue in promotional materials. 

Screenshots in brochures obtained by New York Focus indicated that in one three-month stretch, the system scanned 2.2 million people and there were more than 190,000 alerts. The vast majority of those were for harmless objects like umbrellas, strollers, eyeglass cases and laptops. In that scenario, only 0.8 percent of the alerts were for actual weapons and just 0.1 percent were for non-law enforcement guns. However, Evolv has claimed that the data in the screenshots is “fictitious” and is “from a demonstration account.”

A report by surveillance tech trade publication IPVM earlier this year noted that Evolv’s full-body scanners were misidentifying other objects as potential weapons, such as Chromebooks. IPVM director of operations Donald Maye told the Daily News that Evolv’s system has a false alert rate of between five and ten percent at settings such as sports stadiums (which lines up with data shown in the disputed screenshot). Maye suggested that the false positive rate would actually be higher at subway system scanners and lead to “secondary screenings” with cops searching commuters.

Engadget has contacted Evolv for comment.