Authorized Investigative Techniques
All lawful investigative techniques may be used in general crimes, racketeering enterprise, and terrorism enterprise investigations. In preliminary inquiries, these Guidelines bar the use of mail openings and nonconsensual electronic surveillance (including all techniques covered by chapter 119 of title 18, United States Code), but do not categorically prohibit the use of any other lawful investigative technique at that stage. As set forth in Part IV below, authorized methods in investigations include, among others, use of confidential informants, undercover activities and operations, nonconsensual electronic surveillance, pen registers and trap and trace devices, accessing stored wire and electronic communications and transactional records, consensual electronic monitoring, and searches and seizures. All requirements for the use of such methods under the Constitution, applicable statutes, and Department regulations or policies must, of course, be observed.