Atlanta officials are seeking answers from Google after a news report said that company contractors had sought out black homeless people in the city to scan their faces to improve Google’s facial-recognition technology.

The New York Daily News reported on Wednesday that a staffing agency hired by Google had sent its contractors to numerous American cities to target black people for facial scans. One unnamed former worker told the newspaper that in Atlanta, the effort included finding those who were homeless because they were less likely to speak to the media.

On Friday, Nina Hickson, Atlanta’s city attorney, sent a letter to Google asking for an explanation.

“The possibility that members of our most vulnerable populations are being exploited to advance your company’s commercial interest is profoundly alarming for numerous reasons,” she said in a letter to Kent Walker, Google’s legal and policy chief. “If some or all of the reporting was accurate, we would welcome your response as what corrective action has been and will be taken.”