Not quite correct. There is no longer such a thing as a separate Customs Agency. All the separate agencies involved in border and immigration enforcement were combined into the Department of Homeland Security, including Agricultural Inspection agents. Even before DHS, these agents from various federal agencies were used interchangeably for border (incoming) inspection. Previously, Agricultural Inspection agents were not armed. When made a part of DHS, they were required to carry firearms, which many objected to. Border Patrol has jurisdiction within 100 miles of the border. Border And Customs Inspection (BCI) agents frequently work with BP agents at highway checkpoints. Sheriff's deputies, DPS officers, and National Park officers frequently work with BP and BCI officers at outgoing inspection. Federal officers have jurisdiction over federal laws, state and county officers have jurisdiction over state laws.