When the sheriff in Suffolk County, New York, requested $700,000 from the U.S. government for an artificial intelligence system to eavesdrop on prison phone conversations, his office called it a key tool in fighting gang-related and violent crime.

But the county jail ended up listening to calls involving a much wider range of subjects — scanning as many as 600,000 minutes per month, according to public records from the county obtained by the Thomson Reuters Foundation.

Beginning in 2019, Suffolk County was an early pilot site for the Verus AI-scanning system sold by California-based LEO Technologies, which uses Amazon speech-to-text technology to transcribe phone calls flagged by keyword searches.