Although the Milwaukee Police Department halted its use of facial-recognition technology in February, the tool continues to shadow criminal cases in Milwaukee County because it was used in investigations before the ban took effect. Facial-recognition systems compare images of unidentified people with databases of known faces and generate possible matches. Civil-rights advocates and defense attorneys say the technology can produce inaccurate results, particularly when identifying people of color, and that private vendors often do not disclose enough information about how their systems were trained. “The reliability of these systems is certainly in question, and particularly the disproportionate risk of inaccuracy when identifying non-white faces,” said Amanda Merkwae, policy and advocacy director for the American Civil Liberties Union of Wisconsin. The department acknowledged in April 2025 that officers had used licenses belonging to other agencies to obtain facial-recognition searches for two to three years, despite having no written policy governing the practice. Around the same time, the department was considering an agreement with Biometrica that could have expanded its access to the technology. Residents and civil-rights groups opposed that proposal, citing the risks of misidentification, racial bias, government surveillance and eroded public trust. Police Chief Jeffrey Norman later announced that department members would be prohibited from using facial recognition and that the department would not seek access to the technology until it developed a policy with the Fire and Police Commission. The prohibition did not erase facial-recognition searches conducted in earlier investigations. Milwaukee police did not answer questions about how they disclose those searches to the Milwaukee County District Attorney’s Office. District Attorney Kent Lovern said his office treats a facial-recognition result as an investigative lead, not as probable cause or the sole basis for obtaining a search warrant. He said information about the technology’s use that reaches prosecutors is provided to the defense in the case file. Deputy District Attorney Matthew Torbenson cited a 2021 home-invasion and sexual-assault prosecution in which another law-enforcement agency used facial recognition on surveillance footage and produced about five potential suspects. Investigators ultimately focused on one person after considering additional evidence, including an identification by the person’s former spouse. Torbenson said all five potential matches were disclosed to the defense. “That is not at all how we’re using it,” Torbenson said, arguing that the risks would be greater if facial recognition were used by itself to identify and charge a suspect. Connor Romenesko, a forensic science practice coordinator with the Wisconsin State Public Defenders Office, said defense lawyers may be able to obtain the image submitted for a search and some information about the software, but often lack enough detail to evaluate the system’s overall reliability. “The biggest concern I have with these services is that they’re provided by private companies who don’t necessarily provide information about how these systems are trained,” Romenesko said. That lack of transparency can make it “extremely difficult” to challenge a result, he said. Federal research has found that facial-recognition systems can have higher false-positive rates for some racial and ethnic groups, including Black, Asian and American Indian people. Those disparities have fueled calls for stricter limits on the technology, particularly in criminal investigations where an erroneous lead can direct police attention toward an innocent person. Disclosure practices remain another unresolved issue. The ACLU of Wisconsin reviewed police reports from more than a dozen cases that Milwaukee police had identified as involving facial-recognition technology. Merkwae said many of the reports did not mention the technology. “It’s still a big unknown” how many cases involved facial recognition and whether defendants received that information during discovery, Merkwae said. Romenesko said facial-recognition information is sometimes included in initial discovery but may also have to be requested from police or prosecutors. Public defenders are trained to scrutinize phrases such as “investigative lead,” which can signal that the technology was used without being clearly identified, he said. Milwaukee County Chief Deputy District Attorney Jeffrey Altenburg said leads developed early in an investigation are not always initially shared with prosecutors. Once those leads are corroborated through standard investigative work, however, he said the information is included in reports provided to the district attorney’s office and turned over to defendants who are charged. That process leaves open questions about cases in which facial recognition influenced an investigation but was not clearly documented or disclosed. For defendants and their attorneys, the technology’s continuing presence in older prosecutions means the police ban alone may not resolve concerns about fairness, transparency and the ability to contest investigative evidence.