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Circumstantial Evidence in a DUI Case


In a DUI case in California, much of the evidence of impairment is circumstantial in nature. Facts may be proved by direct or circumstantial evidence or by a combination of both. Direct evidence may prove a fact by itself. For example, if a police officer states that he saw a defendant driving a motor vehicle, that is direct evidence of driving. Circumstantial evidence, or indirect evidence does not directly prove the fact to be decided, but is evidence of another fact from which a jury may conclude the truth of the fact in question. For example, evidence of poor performance of field sobriety tests is circumstantial evidence of impairment. What the prosecutor in a DUI case will attempt to do is establish that poor performance of field sobriety tests means that the defendant was impaired to drive a vehicle. One fact is being used to prove another fact. This is indirect or circumstantial evidence.

Although a defendant may be found guilty based on circumstantial evidence, any lawyer defending DUI cases in Los Angeles must be aware of a very important jury instruction on point. CALCRIM 224 states that before a jury may rely on circumstantial evidence to find a defendant guilty, they must be convinced that the only reasonable conclusion supported by the circumstantial evidence is that the defendant is guilty. If two or more reasonable conclusions may be drawn from the circumstantial evidence, and one of those conclusions points to guilt and one points to innocense, the jury must adopt the conclusion that points to innocense.

This is an exellent instruction for the defense in a DUI case and, after the instruction on reasonable doubt, should be the instruction that the defense should stress the most in closing argument. If you think about it, it completely undermines field sobriety test evidence. Poor performance may reasonably be explained by bad balance, tiredness or simply the fact that FST's are hard to perform perfectly for a sober person in daylight conditions. The jury instructions states that the jury must adopt the conclusion that points to innocense. If a defendant is tired, nervous or has poor balance anyway, these are reasonable explanations of poor FST's that the jury must accept. Defending a DUI case in Los Angeles normally involves a critical analysis of the details. It is rare that there is an obvious or simple defense.

If you have been arrested for a DUI in California, please call Los Angeles DUI lawyers Gold & Witham for a free case evaluation. Defending a DUI case successfully requires experience and expert attention to detail.