The plea set up by those of the defendants who were members of the House is a good defence, and the judgment of the court overruling the demurrer to it and giving judgment for those defendants will be affirmed. As to Thompson, the judgment reversed and the case remanded for further proceedings.
Hallet Kilbourn was subpoenaed to testify before a Special Committee established by the House of Representatives to investigate the bankruptcy of Jay Cooke & Company. Though he appeared, he refused to answer any questions and did not tender requested documents. John G. Thompson, Sergeant-At-Arms for the House, took Kilbourn into custody. Kilbourn continued to refuse to testify and provided no explanation for his refusal. The House resolved that Kilbourn was in contempt and should be held in custody until he agreed to testify and produce the requested documents. The Court found that the House had not the power to punish for contempt. However, House members could not be sued for false imprisonment as they were exercising their official duties and protected by the Speech and Debate Clause, Art. I, § 6, cl. 1. In addition the Supreme Court established several limits in the scope of investigations, called the "Kilbourn Test".
McGeary, M. Nelson (1948). "The Congressional Power of Investigation". Nebraska Law Review28: 516. ISSN0047-9209.
Morgan, Gerald D. (1949). "Congressional Investigations and Judicial Review: Kilbourn v. Thompson Revisited". California Law Review (California Law Review, Inc.) 37 (4): 556–574. doi:10.2307/3477687. JSTOR3477687.