Best Federal Lawyer Michael Leonard discusses cross-examining expert witnesses in federal criminal jury trials

As a best Federal lawyer, Michael Leonard discusses cross-examining expert witnesses in Federal criminal jury trials. As discussed in recent posts, a Federal criminal defense lawyer can take an aggressive and active role with respect to: 1) filing and pursuing pre-trial motions that target and attack the Government’s Rule 16 disclosure of expert witnesses, and 2) obtaining materials, pre-trial, regarding the government’s expert witnesses’ past body of work, including their testimony in other trials and publications. With respect to the cross-examination of the government’s expert witnesses at trial, here are 10 important considerations for executing an effective and meaningful cross-examination of the government’s expert witness at trial:

1. Recognize that you, as defense counsel, are never going to know more than the expert, or be perceived by the jury as on equal footing with the expert in his/her proffered field, discipline, or area of study. In other words, no matter how much experience criminal defense counsel has in this area of testimony, or how much he/she “bones up” on it prior to trial, the jury is never going to perceive you as the one with greater expertise. You will not win that battle. However, you can still appear to be competent and knowledgeable in challenging the bases for the expert’s opinions, his/her methodology, and the limitations of the opinions.
2. Don’t take the approach of “let’s bore and confuse” the jury with respect to the expert’s opinions by getting into the weeds as far as one can go. This will not work. Ultimately, the jury has to “get” where defense counsel is going on cross and have a clear sense of the important takeaways when defense counsel has concluded his/her examination of the expert witness.
3. Reveal the expert’s biases. The jury will still appreciate, for example, that the expert has only ever worked for the government, or for the majority of his/her career; that the expert has testified for the government over and over; that the expert has never provided testimony on behalf of a criminal defendant; that the expert has a prior testifying relationship with this particular United States Attorneys’ Office; that the expert has a prior testifying relationship with these particular prosecutors – among other areas designed to elicit an inference of bias.
4. Reveal what expert is not an expert in – to the extent that is relevant to the case at hand.
5. Reveal the fact that the expert an extraordinarily limited knowledge of the case in which he/she is offering testimony. Establish, for example, that the expert has no knowledge of the defendant, or of the material facts that are in dispute; or of the legal issues that matter in the case.
6. Reveal the limitations that exist with regard to the methodology(ies) employed by the expert.
7. Reveal any material inconsistencies, including by way of impeachment, between the expert’s testimony in this case and his testimony is other, prior matters where he/she opined on the same subject areas.
8. Reveal any inconsistencies between this expert’s testimony and others within his field or area of expertise – including by way of demonstrated differences in learned treaties, peer journals, or peer studies.
9. Reveal the limitations of the expert’s opinions. By way of one example only, with regard to a cell phone tower expert/historical cell site data expert, demonstrate that he/she cannot put the phone in the defendant’s hand; cannot put the phone in a particular, specific location; and of course has no knowledge of the contents of the communications at issue.
10. Reveal the facts, through the expert, that are consistent with your theory of the case.

Of course, there are literally dozens of other considerations that can go into the cross-examination of a government expert witness during a Federal criminal jury trial. This underscores the need for a client-defendant to hire Federal criminal defense counsel who has extensive experience in cross-examining government expert witnesses at trial – in front of Federal juries. Leonard Trial Lawyers has decades of such relevant experience.

Michael Leonard

Leonard Trial Lawyers

October 16, 2023