Important Cases you will want to be aware of:

Kastigar v. United States, 406 U.S. 441, 92 S.Ct. 1653, 32 L.Ed.2d 212 (1972) The Court upheld the constitutionality of the use immunity statute: Kastigar v. United States, 406 U.S. 441, 92 S.Ct. 1653, 32 L.Ed.2d 212 (1972). The power to compel testimony is limited by the Fifth Amendment, and we held that any grant of immunity must be co-extensive with the privilege. We were satisfied, however,[459 U.S. 255] that § 6002 provided this measure of protection and thus "removed the dangers against which the privilege protects." Id., at 449, 92 S.Ct., at 1659. In rejecting the argument that use and derivative-use immunity would not adequately protect a witness from various incriminating uses of the compelled testimony, we emphasized that "[t]he statute provides a sweeping proscription of any use, direct or indirect, of the compelled testimony and any information derived therefrom...." Id., at 460, 92 S.Ct., at 1664. We added that once a defendant establishes that he has testified under a grant of immunity, "the prosecution [has] the affirmative duty to prove that the evidence it proposes to use is derived from a legitimate source wholly independent of the compelled testimony." Ibid. Thus, "immunity from use and derivative use 'leaves the witness and the Federal Government in substantially the same position as if the witness had claimed his privilege' in the absence of a grant of immunity." Kastigar, 406 U.S., at 458-459, 92 S.Ct., at 1663-1664 (quoting Murphy, 378 U.S., at 79, 84 S.Ct., at 1610).

Fortney v US_59_F_3D_117 (1995) Taxpayer filed motion to quash Internal Revenue Services (IRS) summons as issued to third-party recordkeepers. The United States District Court for the District of Nevada, Edward C. Reed, Jr., J., dismissed motion, and taxpayer appealed. The Court of Appeals, Beezer, Circuit Judge, held that: (1) district court lacked jurisdiction over third-party tax summons since third-party neither resided nor was found within jurisdiction of district court; (2) IRS was not required to serve taxpayer attested copy of summonses served on third-party recordkeepers; and (3) taxpayer was not entitled to evidentiary hearing to inquire into government's good faith in seeking enforcement of summonses.

US v Euge_100_S_CT__874 (1980) The United States brought suit for enforcement of an Internal Revenue Service summons requiring taxpayer to appear and provide handwriting exemplars. The United States District Court for the Eastern District of Missouri held that the summons should be enforced, and the taxpayer appealed. The Court of Appeals, 587 F.2d 25,denied enforcement, and certiorari was granted. The United States Supreme Court, Mr. Justice Rehnquist, held that the summons authority of the Internal Revenue Service empowers the IRS to compel handwriting exemplars by its summons authority. (3 dissenting opinions)

US v Giordano_419_F_2D_564 (1970) The United States District Court for the Eastern District of Missouri, Roy W. Harper, Chief Judge, 301 F.Supp. 884, 1