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How to breakdown a San DIego DUI investigation

by | Feb 11, 2014 | DUI Cases |


As a competent advocate it is vital to know how to break down a San Diego DUI investigation. As a former prosecutor I heard countless numbers of defense counsel jump around from fact to fact and not grasp a good sense of the facts.  Most of them followed the police report, jumping from page to page.  Well, the police report is just one piece of evidence that occurred that evening.  It is not the anchor on how to extract what happened that evening.  Prosecutors do the same thing as well.

The issue with a San Diego DUI is twofold.  One, did the officer conduct a proper San Diego DUI investigation. Two, was there an accurate chemical result.  Here, we are going to focus on the officers investigation.  Police are human and can get things wrong.  It is vital to determine from the facts whether it was carried out properly.  To do this it is best to arrange the facts of the DUI investigation into phases. To me,  the easiest way to break it down is to take it from the officers perspective. Lets ask the questions a San Diego DUI officer should as they proceed with a San Diego DUI investigation.

1/2 Foundation

Find out the officers training and experience with San Diego DUIs.  Find out when they started working on the night of the incident.  Ask how many arrests they made that night.  I have seen they sometimes blended the facts of one case with another.


Question 1  Can I pull the vehicle over?


Look for facts that establish a lawful stop. Look for facts that aid the officer in giving suspicion that the driver might be impaired.  Remember, speeding is NOT a sign of impairment (alcohol slows the system).


2  Can I ask the driver out of the vehicle?


From the moment the officer activates their lights they have to be looking for clues of impairment. Their goal is to have evidence to get the driver out of the vehicle. Did the driver take a long time to pull over? Is there an odor of alcohol? Is the drivers movements slow ? Is the drivers eyes red and watery? Does the driver admit drinking? All these are examples of clues.


3  Can I arrest the driver?


The officer asks questions to confirm or dispel their suspicions of impairment. The driver may perform field sobriety tests. The driver walked out of the car with an unsteady gait. Again, this is when the driver is outside the car and the officer has to determine if at the end they have enough to form an opinion to arrest.


4 The Chemical Sample


Facts from a DUI investigation will fall into these phases. The officer then will take a chemical sample. It is vital to ensure the proper procedures were carried out.

The next phases deal with the device that tested the sample itself, as well as whether there could be a reasonable explanation for the blood alcohol level.  However, that is a separate article.

If you can grasp these concepts you have the start of a solid DUI examination.   Good luck!

Hire a Proactive, affordable, and quality defense when you are facing San Diego DUI charges. Whether you have been charged of a San Diego DUI, Poway DUI, La Mesa DUI, Santee DUI, Mission Valley DUI, Clairemont DUI, Point Loma DUI, La Jolla DUI, Carmel Valley DUI, Mira Mesa DUI, Pacific Beach DUI, Del Mar DUI, Carmel Valley DUI, Encinitas DUI, Oceanside DUI, Ocean Beach DUI, Escondido DUI, Vista DUI, San Marcos DUI, Carlsbad DUI, El Cajon DUI it is vital you need to hire an attorney who knows how to defend your rights and can determine if the government can prove their case. Contact the Law Office of Mark Deniz now for a free case evaluation at 858-751-4384 or send an email to [email protected]


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