CAAF Opinion Digest · one opinion, every topic

U.S. v. Knapp, 73 M.J. 33

Decided Jan 15, 2014 · No. 13-0512/AF · September 2013 Term · Opinion (PDF)

Digested under 12 topics

Military Justice Personnel: Military Judge: Duties and Responsibilities

  1. if a witness offers human lie detector testimony, the military judge must issue prompt cautionary instructions to ensure that the members do not make improper use of such testimony

Military Justice Personnel: Court Members: Generally

  1. it is the exclusive province of the court members to determine the credibility of witnesses

Core Criminal Law Subjects: Evidence: Generally

  1. where an appellant has not preserved an objection to evidence by making a timely objection, that error will be forfeited in the absence of plain error; a timely and specific objection is required so that the court is notified of a possible error, and so has an opportunity to correct the error and obviate the need for appeal; to be timely, an objection must normally be made before the answer is given, although some courts permit objections or motions to strike immediately after the answer

Core Criminal Law Subjects: Evidence: Character

  1. the authority to introduce character evidence under MRE 608(a) does not extend to human lie detector testimony

Core Criminal Law Subjects: Evidence: Credibility

  1. it is the exclusive province of the court members to determine the credibility of witnesses
  2. where an AFSOI agent testified that, using his specialized training, he was able to determine from specific nonverbal clues that appellant was being deceptive when he provided an innocent account of the events in question, this testimony was impermissible human lie detector testimony and improperly usurped the members’ role in determining witness credibility

Core Criminal Law Subjects: Evidence: Instructions on

  1. if a witness offers human lie detector testimony, the military judge must issue prompt cautionary instructions to ensure that the members do not make improper use of such testimony

Core Criminal Law Subjects: Evidence: Opinion Testimony

  1. so-called human lie detector testimony, which is an opinion as to whether a person was truthful in making a specific statement regarding a fact at issue in the case, is inadmissible
  2. where an AFSOI agent testified that, using his specialized training, he was able to determine from specific nonverbal clues that appellant was being deceptive when he provided an innocent account of the events in question, this testimony was impermissible human lie detector testimony and improperly usurped the members’ role in determining witness credibility

Core Criminal Law Subjects: Evidence: Waiver

  1. where an appellant has not preserved an objection to evidence by making a timely objection, that error will be forfeited in the absence of plain error; a timely and specific objection is required so that the court is notified of a possible error, and so has an opportunity to correct the error and obviate the need for appeal; to be timely, an objection must normally be made before the answer is given, although some courts permit objections or motions to strike immediately after the answer

Core Criminal Law Subjects: Witnesses: Generally

  1. it is the exclusive province of the court members to determine the credibility of witnesses

Trial Stages: Appeals: Harmless / Prejudicial Error

  1. under the plain error standard of review, an obvious error materially prejudices the substantial rights of the accused when it has an unfair prejudicial impact on the court members’ deliberations
  2. under the circumstances of this case, where an AFSOI agent offered impermissible human lie detector testimony when he testified that, using his specialized training, he was able to determine from specific nonverbal clues that appellant was being deceptive when he provided an innocent account of the events in question, the error was clear and obvious and materially prejudiced appellant’s defense, where the human lie detector testimony was not offered on a peripheral matter or even as a building block of circumstantial evidence, but on the ultimate issue in the case - whether appellant was truthful as to the charge, and where the military judge failed to appropriately instruct the members to disregard this testimony

Trial Stages: Appeals: Preservation of Error / Plain Error

  1. where an appellant has not preserved an objection to evidence by making a timely objection, that error will be forfeited in the absence of plain error; a timely and specific objection is required so that the court is notified of a possible error, and so has an opportunity to correct the error and obviate the need for appeal; to be timely, an objection must normally be made before the answer is given, although some courts permit objections or motions to strike immediately after the answer
  2. with respect to plain error standard of review, appellant has the burden of establishing (1) error that is (2) clear or obvious and (3) results in material prejudice to his substantial rights
  3. under the plain error standard of review, in determining whether an error was clear or obvious, appellate court looks to law at the time of the appeal
  4. because the condemnation of human lie detector testimony easily predated appellant’s trial, the error in this case was clear or obvious
  5. under the plain error standard of review, an obvious error materially prejudices the substantial rights of the accused when it has an unfair prejudicial impact on the court members’ deliberations

Trial Stages: Appeals: Standards of Review, Burdens, etc.

  1. where an appellant has not preserved an objection to evidence by making a timely objection, that error will be forfeited in the absence of plain error; a timely and specific objection is required so that the court is notified of a possible error, and so has an opportunity to correct the error and obviate the need for appeal; to be timely, an objection must normally be made before the answer is given, although some courts permit objections or motions to strike immediately after the answer
  2. with respect to plain error standard of review, appellant has the burden of establishing (1) error that is (2) clear or obvious and (3) results in material prejudice to his substantial rights
  3. under the plain error standard of review, in determining whether an error was clear or obvious, appellate court looks to law at the time of the appeal
  4. under the plain error standard of review, an obvious error materially prejudices the substantial rights of the accused when it has an unfair prejudicial impact on the court members’ deliberations
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Last updated by the court: Oct 13, 2026 · mirrored Oct 29, 2026 · Always confirm a holding against the opinion itself (linked from each case name).