In a DWI case, the defense attorney may attempt to impeach a prosecution witness. The process of impeachment is intended to discredit the witness as a reliable source of information. Successful impeachment of a witness renders the witness less worthy of belief by a jury.

The most common method of impeachment is the showing of a prior inconsistent statement, action, or omission by the witness. The showing of a prior inconsistent statement by the witness demonstrates that the witness’s current testimony contradicts their own previous statement or actions. In essence, when a DWI defense attorney impeaches a witness by using a prior inconsistent statement, the attorney is showing that the witness has changed their story and seems unreliable. Prior inconsistent statements damage a witness’s credibility because they show that the witness has changed their story.

A second method of impeachment is the use of character evidence. This form of impeachment is used to show that a witness has some particular trait that renders their testimony less credible. For example, the defense attorney in a DWI case may show that a prosecution witness is a convicted felon or suffers from some psychological problem, such as a serious memory defect. In essence, this type of impeachment may be used by a DWI defense attorney to show that a witness is not trustworthy because of some personal issue. The most common forms of characteristic impeachment include the conviction of a crime, a defect in memory or perception, and past untruthfulness of a witness.

A third method of impeachment involves gathering information that makes a prosecution witness seem less reliable within the context of the particular DWI trial. A DWI defense attorney may gather information about the witness that shows that they have a financial stake in the outcome of the case or that they may be prejudiced against one of the parties in the case. In essence, this form of impeachment may be used by a DWI defense attorney to show a jury that less weight should be given to a witness’s testimony because of their particular relationship to the case.

A DWI defense attorney may attempt to impeach the testimony of expert witnesses in the case. A toxicologist or police laboratory technician may be called in to testify regarding medical and scientific evidence which will be presented at trial. A DWI defense attorney may attempt to impeach the testimony of these witnesses on the basis that these experts do not possess the requisite special training to offer an opinion or conclusion in the case. The opinion of an expert may also be challenged by a DWI defense attorney on the basis that an essential or foundational fact upon which the expert’s opinion is based has been the subject of contradictory testimony.

Another way that a DWI defense attorney can impeach a prosecution witness is on the grounds of bias. For example, a DWI defense attorney may show that an expert witness gains a substantial amount of their income from testifying for the prosecution. The attorney may attempt to show that the witness is biased because they are hired for the sole purpose of providing testimony against the defendant and that it is in the expert’s best interest if the defendant be convicted. Such experts may be questioned by the defense in a DWI case regarding the number of times they have testified and the payments they have received for their testimony.

The DWI defense attorney may also impeach the testimony of the arresting officer in the case. The attorney may attempt to show that the officer made a purely subjective decision about the defendant’s intoxication or impairment in the case. The DWI defense attorney may also impeach the arresting officer about departmental quota systems for DWI arrests in an attempt to show the officer’s possible reasons for testifying falsely against the defendant. A DWI defense attorney may impeach the arresting officer about credible allegations of police officer misconduct previously filed against the officer. The attorney may obtain information about prior complaints against the police officer in other DWI cases showing the officer engaged in similar types of misconduct. If there is indeed evidence of other complaints against the officer, this fact would be useful in impeaching the officer’s credibility.

The attorneys with the DWI GUYS are experienced in handling DWI cases. If you need a lawyer with knowledge and experience to handle your DWI case, call the DWI GUYS at 1-800-394-8326.

DISCLAIMER: The exclusive purpose of this article is educational and it is not intended as either legal advice or a general solution to any specific legal problem.  Corporate offices for The DWI GUYS are located at 432 N. Franklin Street, Syracuse, NY 13204; Telephone No.: 1-800-394-8326.  Prior results do not guarantee a similar outcome.