Also known as: material witness · material-witness · key witness
Written by attorneys · grounded in primary & secondary sources — see below
A witness whose testimony is central to a pending proceeding. The status requires a judge's recusal when the judge previously served in that role and subjects the witness to supervised detention or deposition when prolonged unavailability is shown.
Attorney Ming Ma previously testified in a coverage dispute about the meaning of an insurance endorsement. When the same language arises in a new storm-damage claim assigned to her as judge, the parties move to disqualify her. The court grants the motion because her earlier testimony addressed the precise factual issue now in controversy.
Police detain Michelle Murphy after she observes a robbery and can identify the perpetrator. The government seeks to hold her as a material witness because her account supplies the only direct evidence of the defendant's presence at the scene. The court orders supervised release rather than custody after finding less restrictive conditions adequate.
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Mason McCarthy and an investigator agree to pay a shipping supervisor to alter his account of container loading. The supervisor's expected testimony would directly contradict the smuggling charges. Prosecutors charge conspiracy because the plan targets a material witness whose truthful evidence would exonerate the defendant.
The prosecution withholds statements from Melissa Mills that contradict the state's account of a murder. Defense counsel later shows her account would have undermined the sole eyewitness identification. The court finds the suppressed evidence material because Mills's testimony could have altered the outcome.
A DNA analyst prepares a report linking Monica Morgan to a crime scene. The report rests on laboratory observations that the analyst would have to explain at trial. The court treats the analyst as a material witness whose live testimony is required for confrontation purposes.
Michael Miller, a former first mate, supervised cargo loading central to a smuggling prosecution. His vessel will remain at sea for years. The defense moves to depose him because his account directly negates the captain's involvement. The court grants the motion to preserve the material testimony.
A judge must step aside if she was a material witness concerning the matter in controversy. The rule focuses on whether the judge's earlier testimony addressed a disputed factual issue that remains central to the present case.
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The court must supervise detention of material witnesses to eliminate unnecessary custody. The government must report biweekly on any witness held more than ten days and explain why release or a deposition is not appropriate.
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Yes. Exceptional circumstances exist when a material witness cannot reasonably appear at trial for an extended period. The court may order a deposition to preserve the testimony when justice requires it.
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A judge is disqualified when she has been a material witness concerning the proceeding. The statute parallels the Model Rules and requires recusal even without personal bias if the judge's prior testimony concerned the same controversy.
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…against the accused.” Ibid. Sir Walter Raleigh’s case illustrates the point. State authorities questioned Lord Cobham, the key witness against Raleigh, outside his presence. They then used those testimonial statements in court against Raleigh. And when Raleigh asked to face and to challenge his accuser, he was denied that…