Human trafficking is a crime that takes place largely in the shadows. Victims, who are mostly women and children, often lack legal documentation in the country where they are forced to work or perform sex acts, and many fear reprisals if they go to authorities. Perpetrators, for obvious reasons, take great pains to conceal their behavior by laundering money and keeping their operations quiet. And others who engage in trafficking-related criminal activity -- such as individuals looking to connect with trafficked sex workers -- also have powerful incentives to hide their participation. Recently, law enforcement agencies and organizations that help victims of human trafficking have begun using artificial intelligence tools to overcome this lack of visibility.