An innocent woman forced to her knees, held at gunpoint, handcuffed and surrounded by multiple San Francisco, California police officers can proceed with her lawsuit for false arrest. The Ninth Circuit US Court of Appeals on Monday ruled that the officers were potentially liable for using excessive force against Denise Green after an automated license plate reader (ALPR or ANPR in Europe) mistakenly flagged her vehicle as stolen. On March 30, 2009, a camera mounted on a police car on Mission Street took a blurry photo of Green's burgundy Lexus ES300 which the automated system confused for a stolen gray GMC pickup truck.

After being alerted to the "hit" over the radio, San Francisco Police Sergeant Ja Han Kim saw Green's car pass by. He neither confirmed the license plate number on the car nor the make and model of the stolen vehicle. Instead, he called for backup and initiated a high-risk felony stop. Green, a 47-year-old black woman, was held for twenty minutes before one of the six officers got around to checking her license plate.

Green sued for false arrest, but a federal district granted the officers immunity. The appellate judges disagreed, finding evidence of negligence. San Francisco Police Department policy recognizes ALPR readings are often faulty. Officers are supposed to verify the vehicle and the license plate before performing any stop. Sergeant Kim thought the camera squad car would have performed the verification, and the camera car driver, Officer Alberto Esparza, thought the arresting officer would be responsible. The department had no clear policy on who had to perform the check.

"Sergeant Kim had several opportunities to confirm the license plate number with dispatch and even spent time stopped behind Green at a red light, and nothing obscured Green's license plate throughout the incident," Judge William K. Sessions III wrote for the appellate panel. "A rational jury could conclude that it was unreasonable for Sergeant Kim to fail to double check the plate number in the absence of express confirmation from Officer Esparza."

The officers had no reason to suspect Green was dangerous, as she was cooperative throughout the entire encounter. The panel held the amount of force used was arguably excessive. The judges ruled that a jury needs to decide whether the city or the officers should be held accountable for their conduct.

The ACLU of Massachusetts Technology for Liberty Project says cases like this will become more common as law enforcement increasingly turns to these systems.

"Using tools like license plate readers and pre-crime 'intelligence-led' policing algorithms, police officers are relying more and more on computers to tell them who is dangerous, who is wanted for crimes, and who is suspect," Kade Crockford, the project's director, wrote regarding the case. "And while police officers can make mistakes on their own, without a helping hand from malfunctioning technological systems, the buck must stop with the officers in the flesh."

A copy of the decision is available in a 170k PDF file at the source link below.