Navy Seaman Brian Kretz, a construction mechanic deployed here with Navy Mobile Construction Battalion Four, repairs an electric wire on a 50-ton tractor, Dec. 16, 2008. NMCB Four is on a six-month deployment to U.S. Naval Station Guantanamo Bay and supports many of Joint Task Force Guantanamo's construction projects. JTF Guantanamo conducts safe, humane, legal and transparent care and custody of detained enemy combatants, including those convicted by military commission and those ordered released. The JTF conducts intelligence collection, analysis and dissemination for the protection of detainees and personnel working in JTF Guantanamo facilities and in support of the Global War on Terror. JTF Guantanamo provides support to the Office of Military Commissions, to law enforcement and to war crimes investigations. The JTF conducts planning for and, on order, responds to Caribbean mass migration operations.