Johnson v. United States

(after stating the facts as above).

Zeal in performing official duty is to be commended, and activity by the proper officials in detecting violations of the law by using all proper means and methods is not at all inconsistent with indifference to any particular result other than the efficient administration of the law. But when a marshal, without authority of law or instructions from competent authority, hires a private individual to detect suspected violations of a particular law and pays such person out of his own private funds, and upon the information furnished by such person, who admits that he also participated in the offense under investigation, prosecution is instituted against certain persons, and the principal evidence relied on is to come from such employed detective, a situation is presented where, if on the trial a jury panel is exhausted, and it becomes necessary to draw jurymen from the bystanders, a defendant may well object to the drawing of such jurymen by the marshal or his deputies, upon the ground that he is not an indifferent person, and, if there be no denial of the facts and circumstances shown, the duty of the court is to specially appoint a fit person,…