Human traffickers prey on some of the most vulnerable members of society, exploiting them for compelled labor, services, or commercial sex, often through invisible schemes of psychological coercion that can be exceptionally difficult to detect. Trafficking crimes pose serious threats not only to the rights, freedom, and dignity of individual victims, but also to the public health and safety of communities and the rule of law. While combating trafficking threats is therefore an urgent priority, it presents numerous challenges that law enforcement must overcome to detect hidden trafficking crimes, secure the cooperation of traumatized victims as essential witnesses, and develop sufficient evidence to bring human traffickers to justice.