Constitution of the United States, Amendment V.
“A capital crime is such crime as the law declares punishable by death penalty.”—Bouvier's Law Dictionary, Vol I, p. 284.
“An infamous crime is such crime as the law declares punishable by imprisonment in a state prison.”
A grand jury, or an indictment, or a presentment jury, or an inquest jury, is a jury (differing as to numbers in different States) for the purpose of investigating alleged crimes. If, upon investigation, the jury believes the accused person has either committed the act or has had a part in the crime, it will draw up a formal accusation in writing. This accusation is called an indictment and is presented to the court. In a few States a person may be brought to trial for violation of a law of the State upon information filed by the prosecuting attorney.
A petit jury, or trial jury, is a jury of twelve men selected by the court—according to a law determining the manner—to hear the accusation against the person charged along with the evidence submitted during the trial in court. After hearing the evidence and receiving from the judge instructions concerning the law governing the case, the jury will determine whether the accused person is guilty or not. The Federal government, and most of the States, require a unanimous verdict. If the jury disagrees they report such to the court (the judge) and they are dismissed and the case may be tried again with a different jury.
“Constitutional guaranties of the right of trial for crime only on indictment by a grand jury, imply a common law grand jury of whose number at least twelve men concur in finding the indictment, but by provision in state constitutions a smaller number of grand jurors than required by common law and concurrence of a smaller number than twelve in the finding of an indictment may be authorized.”
“A grand jury affords a safeguard against the unwarranted ignominy of being put on public trial for an offense which there is no reasonable ground to believe the accused has committed.”
“The grand jury is to investigate the cases of those who have been arrested and held under preliminary information on oath by private accusers; and it may also investigate cases of supposed crime of which it has knowledge or to which its attention may be called by the public prosecuting officer. Its proceedings are secret and its members are sworn not to subsequently divulge them.”—McClain's Constitutional Law.
Constitution of the United States, Amendment V.
“The rule of procedure generally recognized is that when an accused person has been put on trial under a valid indictment in a court having jurisdiction of the case, and a jury has been empaneled and sworn to try the case and give a verdict, and a verdict of not guilty is given—the accused cannot be again put on trial for the same crime, or any included crime for which he might have been convicted in that prosecution.”—Cyclopedia of American Government, Vol. II, p. 251.