For the first time, Chicago police used a facial recognition program to identify, capture, and convict a robbery suspect. In May, Pierre D. Martin, 35, was convicted in a bench trail for a robbery he committed in February of last year. He received a 22 year sentence this month.

“This case is a great example that these high-tech tools are helping to enhance identification and lead us to defendants that might otherwise evade capture,” Cook County State’s Attorney Anita Alvarez said in a statement reported by the Chicago Sun-Times.

Martin, a man with an extensive criminal history, had robbed several people at gunpoint on the CTA, Chicago’s city transit system, where the transit authority’s surveillance cameras caught him. A still from the surveillance video was compared to the 4.5 million-person criminal booking photos and he was identified as the number one choice.

The system was purchased from NeoFace technology with a $5.4 million federal grant the Chicago Police Department applied for. The system went live in June of 2013.

The American Civil Liberties Union, though, is wary of the system. The ACLU’s stance is that the system should only be used if police feel they already have probable cause that the person being looked for was involved in a crime. The ACLU also fears that the system could be used in random sweeps for regular people in the streets even if no crime is involved.

But Jonathan Lewin, a NeoFace employee working with the Chicago PD, says that is not a worry. “There will absolutely be no random surveillance–and facial recognition–of subjects in the public way,” he said last year when Martin was initially arrested.