Michael Williams gunshot detection wrongful arrest

Occurred: May 2020

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Michael Williams, a 63 year-old retiree living in Chicago, was wongly arrested and jailed for nearly a year after Chicago Police Department (CPD) officers accused him of shooting a neighbour sitting next door to him in his car based on an 'unreliable' ShotSpotter gunshot detection alert.

At Williams' trial, prosecutors cited ShotSpotter sensors to bolster their case. But, according to a motion (pdf) filed by Williams' attorney, the company’s algorithms had initially classified the sound as a firework and the location co-ordinates had been altered. The admission persuaded the prosecutors to withdraw ShotSpotter evidence against Williams and the judge to dismiss the charges.

In July 2022, the MacArthur Justice Center filed a class-action lawsuit (pdf) on behalf of Williams and two other claimants for mental anguish, loss of income, and legal bills. The suit also sought a court order barring the technology’s use in Chicago. 

Operator: Chicago Police Department
Developer: SoundThinking/ShotSpotter
Country: USA
Sector: Govt - police
Purpose: Detect gunfire
Technology: Gunshot detection system; Deep learning
Issue: Accuracy/reliability; Oversight/review
Transparency: Governance; Black box; Marketing


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