Senate Foreign Relations Committee Democratic staff issued a scathing report about the activities of CBP personnel in Guatemala in January 2020 (original link). The CBP agents were in Guatemala on a support mission funded by the State Department’s Bureau of International Narcotics and Law Enforcement Affairs.
According to the report, the CBP personnel deployed near Guatemala’s border with Honduras and confronted a “caravan” of Honduran migrants directly, apprehending many of them—including families—and transporting them back into Honduras aboard unmarked, rented vehicles.
For months, the report alleges, the Department of Homeland Security failed to respond to Foreign Relations Committee staff inquiries, and lied to the State Deparment—which funded the agents’ presence—about the role that the CBP agents had played.
— DHS Run Amok? A Reckless Overseas Operation, Violations, and Lies (Washington: Senate Foreign Relations Committee Democratic staff, October 13, 2020) https://www.foreign.senate.gov/imo/media/doc/Final%20INL%20DHS%20Report.pdf.