A Joint Review of Law Enforcement Cooperation on the Southwest Border between the Federal Bureau of Investigation and Homeland Security Investigations [open pdf - 3MB]
"The U.S. Southwest border with Mexico spans nearly 2,000 miles. The region presents unique challenges to law enforcement, and, because multiple law enforcement agencies engage in investigative activity along the Southwest border, effective cooperation among such agencies is important to ensure that all agencies perform their work without jeopardizing the safety of law enforcement and the public. The U.S. Department of Justice's (DOJ) Federal Bureau of Investigation (FBI) and the U.S. Department of Homeland Security (DHS) Immigration and Customs Enforcement's (ICE) Homeland Security Investigations (HSI) are among the largest U.S. federal investigative law enforcement agencies. [...] For this review, the DOJ Office of the Inspector General (DOJ OIG) and the DHS Office of Inspector General (DHS OIG) jointly evaluated cooperation between the FBI and HSI on Southwest border criminal investigations."
Department of Homeland Security Office of the Inspector General: https://www.oig.dhs.gov/