A supporting deposition is a written instrument accompanying or filed in connection with an information, a simplified information, a misdemeanor complaint or a felony complaint, subscribed and verified by a person other than the complainant of such accusatory instrument, and containing factual allegations of an evidentiary character, based either upon personal knowledge or upon information and belief, which supplement those of the accusatory instrument and support or tend to support the charge or charges contained therein.
New York Legal Code