When investigating persons acting as fences, normally, immunity should not be sought for fences in order to prosecute thieves. Special consideration should also be given to the possibility of post-conviction grand jury proceedings for thieves in an effort to identify those fences with whom the thief has dealt. Informants familiar with the technicalities of particular fields of business enterprise should be cultivated to provide information about fencing operations. The use of court-authorized electronic surveillance may often be necessary in such investigations. See 18 U.S.C. § 2516(c).
[cited in JM 9-61.400]