Prosecutions by information are those not founded on a
presentment or indictment. The information is a written
accusation filed in court by the prosecuting officer. In certain
classes of cases, the leave of the court must be first asked in
some jurisdictions. It is not necessary that it be supported by
any previous statement or complaint under oath. The officer who
prepares it acts under an oath of office, and that is deemed
sufficient to give probability to whatever charges he may make.

If the defendant has already been bound over by a committing
magistrate, such an information may take the place of the
original complaint on which the arrest was made. If he has not
yet been arrested, or if he was arrested and discharged by such a
magistrate, the filing of an information is accompanied by a
request for the issue of a warrant for his arrest from the court.
Such a paper is called a bench warrant, and is granted whenever
necessary, whether upon a presentment, indictment, or
information.

An information may be amended by leave of the court at any time.
A presentment or indictment cannot be. They, when returned to
court, are the work of the grand jury, and they end its work. An
amendment of a legal process can logically be made only by the
hand which originally prepared it. This rule leads to the escape
of many a criminal. If prosecuted by indictment, the case
against him must be substantially proved--in whole or part--as
there stated, or he goes free. Prosecuting officers therefore
naturally prefer to proceed upon information whenever the law
permits it.