In states where by constitutional provision indictment is still essential, it is usually required in cases of treason and felony; but Amendment V uses somewhat different language and specifies the crimes triable only on indictment in the federal courts as those which are capital or otherwise infamous. Capital crimes are those for which punishment by death may be imposed; and infamous crimes are those subjecting the guilty person to an infamous punishment. The infamy which is referred to in this description is infamy in the punishment which may be imposed, and not infamy in the nature of the crime itself. An infamous punishment not capital is punishment by imprisonment in a penitentiary, as distinct from imprisonment in a county jail (Mackin v. United States).

Crimes which are not capital or otherwise infamous may be prosecuted in the federal court on indictment, but in such cases indictment is not essential under the constitutional provision. There must, however, be some recognized form of accusation, and the usual form in such cases is called an information, which is a complaint made under oath and presented by the prosecuting officer to the court, charging the crime in substantially the same manner which is usual in an indictment.