What is the primary mission of the Department of Homeland Security's HSI?

The primary mission of the Department of Homeland Security's Homeland Security Investigations (HSI) is to investigate and enforce immigration and customs laws. This includes a broad range of responsibilities that cover various aspects of illegal immigration, customs violations, and human trafficking, among other criminal activities. HSI plays a crucial role in maintaining the integrity of the U.S. borders and ensuring that laws related to immigration and customs are upheld.

The focus on immigration and customs enforcement enables HSI to tackle critical issues that affect national security and public safety directly. By conducting investigations and collaborating with other law enforcement agencies, HSI addresses illegal activities that may undermine lawful immigration processes and the overall security of the nation.

The other options, while important functions of the Department of Homeland Security, either represent broader missions or specific operational objectives that do not encapsulate the core focus of HSI. For example, the enforcement of federal criminal laws encompasses a wide range of laws beyond immigration and customs, while promoting national security and managing emergency responses are more generalized goals of DHS that include contributions from various divisions, not just HSI.