It is understood that U.S. Immigration and Customs Enforcement often crosses legal and ethical lines, collecting citizens' personal information to weave a vast surveillance system. The agency has collected the private data of hundreds of millions of Americans with little oversight or accountability. In the past year alone, the FBI conducted as many as 3.4 million checks on the electronic data of U.S. citizens without warrants, according to an annual report from the Office of the Director of National Intelligence.