DUI Evidence

Posted on 12-21-2015 by
Tags: Trending News & Topics

People who have been arrested for or charged with a DUI offense often want to know what type of evidence will be used against them if they go to trial. Under the rules of discovery, all relevant evidence must be turned over to the defense. Usually, defense counsel will be provided a copy of the complaint, incident reports and chemical test results at the defendant’s DUI arraignment hearing. Any additional evidence usually must be requested by sending an informal discovery request to the prosecutor.

In most cases, the account of the arresting officer will be one of the prosecution’s strongest pieces of evidence. The officer will prepare an incident report and will describe the reasons for pulling over the defendant. The officer will further describe his or her initial interaction with the driver and what led the officer to believe that the driver was under the influence of alcohol or drugs. The officer can testify regarding the driver’s performance on the field sobriety tests and other aspects of the DUI investigation.

In order to challenge the officer’s account of the DUI arrest and investigation, it may be critical to obtain other sources of evidence. In many cases, the defense will be able to obtain the dash cam video footage showing the defendant’s driving conduct and the vehicle stop. In many cases, the recording will show that the driving conduct on the video does not match the officer’s description. In these cases, the defense may file a motion under California Penal Code Section 1538.5 to challenge the basis of the vehicle stop. If the stop is found to be without reasonable or probable cause, the resulting evidence will be suppressed and the case will likely be dismissed.

In addition, audio or body camera recordings may also be helpful in challenging the officer’s account. In many cases, the officer will claim that the defendant was slurring his or her words; however the audio recording or camera footage will show the driver is speaking clearly or does not appear intoxicated. Body cameras are slowly being implemented by law enforcement agencies and as this type of evidence becomes more prevalent it will be useful in mounting successful DUI defenses.

One of the most important pieces of evidence is the results of chemical testing. Without these, the prosecutor would be unable to prove that the defendant is guilty of driving under the influence of alcohol or drugs (unless the driver is charged with DUI refusal in which case there would be no chemical test results). For drivers who take the Breathalyzer test, it may be necessary to obtain the device’s maintenance and calibration records. If the Breathalyzer machine was not functioning properly when the breath sample was taken, the accuracy of the results may be disputed. For drivers who choose the blood test, the defense may want to see the chain of custody reports for the blood sample to ensure that the sample was not mixed up with another driver’s blood. If the prosecution is unable to establish a clear chain of custody, the evidence will likely be unusable.

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