State v. Dunning

A police officer should be prohibited from testifying as an expert regarding technical or scientific matters if he has no expertise or formal training on the subject.

Defendant was convicted of attempted murder, for her part in a “dispute over cattle [that] ended with two people shot dead.” On appeal defendant argued that the trial court erred in refusing to allow her to impeach a witness by questioning him regarding his probationary status, and also when it allowed a police officer to testify as an expert in the area of memory recall. The Court of Appeals held that the trial court correctly prohibited questions about the witness' probationary status. However, the Court held that the trial court erred in allowing the officer to testify as an expert. The Court found that the officer had no formal training in the area of memory recall, and only derived his knowledge of the subject from materials available to the general public. Thus, the trial court committed prejudicial error in allowing him to testify on the subject. Reversed and remanded.