In a Los Angeles DUI trial, the prosecutor will typically call a chemist from the crime lab as the second witness - the prosecution "expert." The crime lab technician's testimony will always point toward your guilt, but an experienced Los Angeles DUI attorney will aggressively cross-examine this witness to create reasonable doubt in your guilt and also call independent experts to contradict the prosecution witness's testimony.

The prosecutor will first ask the crime lab technician to recite a long list of training and education that qualifies him as an "expert" in chemical testing for blood alcohol content. Then the prosecutor will ask the crime lab chemist to testify about the chemical test you took following your Los Angeles DUI arrest.

Crime lab technicians must use general scientific principles and assumptions to reach conclusions about your BAC. These assumptions don't reflect the many variables present from person to person, such as your alcohol tolerance, size, absorption rate, or any meals you ate before drinking.

The prosecutor may also ask the expert to testify about how field sobriety tests help police to determine whether a driver is under the influence of alcohol or drugs. The expert may comment on your field sobriety test performance and what this says about your BAC.

The crime lab technician will likely make hypothetical statements to support the allegation that you were driving under the influence. Unfortunately, experts are allowed to use hearsay - out of court statements offered to support testimony - in forming opinions, hypotheticals, and conclusions.

Once the prosecutor completes direct examination of the crime lab expert, your Los Angeles DUI attorney can begin cross-examination. Your defense lawyer will take this opportunity to thoroughly discredit the crime lab technician and punch holes in the prosecutor's case.

Cross-examining the prosecutor's expert in a Los Angeles DUI case is an opportunity for the defense attorney to testify, much like the questioning of the police officer who arrested you. Your Los Angeles DUI attorney will ask leading questions that can be answered only with a yes or no. This method of questioning allows your defense attorney to make statements to the jury, and the prosecution expert will have no choice but to agree.

An effective Los Angeles DUI attorney crafts your defense strategy with the knowledge that it's far better to score points with the prosecution's expert than with your own defense witness. Jurors are aware that the crime lab technician is there to support the prosecution, so when the prosecutor's expert appears to side with the defense, jurors will pay attention.

Cross-examination of the prosecution expert by a skilled Los Angeles DUI attorney will diminish or even eliminate the impact of the crime lab technician's testimony and help create reasonable doubt in your guilt.