WASHINGTON — Sen. Rand Paul, R-Ky., leads a committee on Capitol Hill that has jurisdiction over the Department of Homeland Security. That agency has been under heightened scrutiny after federal agents shot and killed two U.S. citizens who were protesting immigration enforcement operations in Minneapolis last month. In letters to the heads of three federal immigration agencies, Paul wrote, “The Department of Homeland Security has been provided an exceptional amount of funding to secure our borders and enforce our immigration laws. Congress has an obligation to conduct oversight of those tax dollars and ensure the funding is used to accomplish...