A Minnesota (AO 90) Subpoena to Testify at a Deposition in a Criminal Case is a legal document issued by a court officer that requires an individual to appear in court and provide sworn testimony in a criminal case. This type of subpoena is issued by the court clerk, usually on behalf of a prosecutor or defense attorney, and is served to the individual named on the document. This document specifies the date, time, and place of the deposition and must be followed by the individual. There are two types of Minnesota (AO 90) Subpoena to Testify at a Deposition in a Criminal Case. The first is a Grand Jury Subpoena, which is issued by a grand jury as part of a criminal investigation and requires the individual to appear before a grand jury. The second is a Regular Subpoena, which is issued by a prosecutor or defense attorney and requires the individual to appear in court for a deposition.