Discrediting expert witnesses
Discrediting expert witnesses
It should not be surprising if the prosecution in a computer crime case calls expert witnesses to explain the manner in which the alleged crime was committed, or to explain the manner in which it was detected. For instance, if the computer crime was alleged to involve changes in a computer's programming such that certain amounts were credited to the defendant's account, a systems analyst might be called to testify as to how the programming was changed. A jury may react positively to an expert merely because he or she does not understand the expert's vocabulary. A juror may also have a positive reaction to an expert witness if the juror is impressed with the expert's credentials or the expert is able to make his or her testimony completely comprehensible to the lay person. However, it is also possible that a general distrust of experts, the dislike of computers and computer technology, or the inability of the expert to communicate in lay terms will cause the jury to react negatively to the expert.
Where it appears that the expert is influential, the defense must undermine the jury's belief in the expert's testimony. Where technical terms are used, the defense may translate them into lay terms, particularly effective if by so doing the term's significance is diminished.FN53 If publications or speeches, cited in the expert's educational qualifications, contain statements contradicting the position of the expert at trial, such contradicting statements are useful to refute the expert's testimony. However, if the expert has alienated the jury, the role of the defense counsel is to provide the expert with more opportunities to alienate the jury. It is not uncommon for an expert to believe that qualification of his or her testimony will weaken the side offering that testimony. Such experts should be cross-examined thereby making them even less credible, a result, as they become more dogmatic about their position. To discredit the testimony of a prosecution witness, counsel should use his or her own experts. These experts provide valuable assistance in planning the cross-examination, and in alerting counsel to the logical and practical infirmities of the prosecution's position. Under some court rules, it is possible to have the expert sitting next to counsel at the time of the cross-examination.FN54 The expert witness can also testify as part of the defense case.