I am Joel Brand, a California DUI defense attorney, and in this post I want to walk you through something that surprises almost every person I speak with after an arrest: the prosecutor already has a file on you, and it is much thicker than most people expect. Understanding what is in that file, how you get to see it, and what it can mean for your case is one of the most practical things you can do in the days after an arrest.
The Basic Idea of Discovery in a DUI Case
In California criminal cases, both sides are entitled to exchange evidence before trial. This process is called discovery. For a DUI, discovery means the prosecutor must turn over every piece of evidence they plan to use against you. That includes documents, recordings, test results, and witness information. The goal of the discovery rules is fairness, but in practice the evidence package the prosecutor holds is far more detailed than most drivers ever imagined when they were sitting in the back of a patrol car.
The Police Report
The police report is usually the centerpiece of a DUI prosecution. It contains the officer's narrative of what happened: why you were stopped, how you drove, what you said, how you performed on field sobriety tests, and how the officer formed the opinion that you were impaired. Reading this report carefully is essential because officers sometimes record details inaccurately, leave out information that helps you, or describe field sobriety tests in ways that do not match what the standardized instructions actually require. My article on common mistakes police make at a DUI stop explains many of the errors that show up in these narratives.
The Breath or Blood Test Results
If you took a breath test, the prosecutor will have the printed result from the evidentiary machine as well as calibration and maintenance logs for that device. A poorly calibrated machine can produce an unreliable reading. If you took a blood draw, the file will include the laboratory report showing the measured blood alcohol concentration along with chain-of-custody records tracking every person who handled the sample. Problems in the chain of custody or in lab procedures can raise serious questions about the accuracy of the result. I cover both of these issues in my articles on bad calibration as a defense and on the rising BAC defense, which applies when your blood alcohol was still climbing at the time you were actually driving.
The DS 367 and the DMV Administrative Package
When an officer arrests you for DUI in California, they fill out a form called the DS 367. This form triggers the administrative license suspension process and is also part of the evidence file. It records important details such as whether you were read your chemical test admonition and whether you complied. Errors on this form can sometimes be used to challenge the suspension. My article on DS 367 mistakes that can help your case goes deeper on this point. You can also learn more about what happens at the DMV side of things by reading about how to prepare for your DMV hearing.
Video and Audio Recordings
Most modern patrol cars carry a dashcam, and many officers wear body cameras. These recordings are part of discovery and can be extraordinarily helpful or deeply damaging, depending on what they captured. A recording that shows you walking steadily, speaking clearly, and behaving calmly can contradict an officer's written description of obvious impairment. A recording that shows the opposite can make the case harder. Either way, you need to see this footage early. My post on police mistakes at a DUI stop describes situations where video directly contradicts an officer's written account.
Field Sobriety Test Records
The prosecutor will have the officer's scoring sheets for any standardized field sobriety tests you performed. These tests, including the walk-and-turn, the one-legged stand, and the horizontal gaze nystagmus test, are supposed to be administered under strictly standardized conditions. If the officer did not follow the correct protocol, or if you had a physical condition, wore certain footwear, or stood on an uneven surface, the scoring can be unreliable. The prosecutor has those sheets, and so should your defense.
Witness Statements and 911 Call Records
If another driver called 911 before or during your stop, that call recording and any written statement from the caller will be in the discovery package. The identity of that caller, the timing of the call, and the exact words used can all matter. A vague or inconsistent 911 report can undercut the basis for the traffic stop itself. The prosecutor is required to disclose any witness statements they have, and your attorney can also file motions to obtain additional material under the Brady doctrine, which requires the prosecution to turn over evidence that could help the defense.
The Officer's Training Records and Disciplinary History
This is a piece of discovery that many people do not know exists. Through a process called a Pitchess motion, your attorney can ask the court to review an arresting officer's personnel file for prior complaints of dishonesty, excessive force, or improper conduct. If the court finds relevant complaints, that information can be used to challenge the officer's credibility. My article on Pitchess motions in DUI cases explains how this works in practice. In addition, if the officer appears on the Brady list, the prosecutor may have an independent obligation to tell you.
How Your Attorney Requests Discovery
After you appear at your arraignment and enter a not-guilty plea, your attorney formally requests the discovery package from the prosecution. In most California counties this happens quickly, but the completeness of what you receive can vary. Your attorney may need to make follow-up requests or file a motion if materials are missing. Delays in receiving evidence, including lab results that are not yet back, are common and are one reason that DUI cases often take several months to resolve. The step-by-step process is described in my article on the DUI court process.
What Happens After Your Attorney Reviews the Evidence
Once discovery is in hand, your attorney analyzes every document for weaknesses in the prosecution's case. Those weaknesses might include a legally improper stop, a machine that was out of calibration, a blood sample with a broken chain of custody, or a field sobriety test that was scored incorrectly. Identified problems can support a motion to suppress evidence under Penal Code section 1538.5, which could reduce or eliminate the evidence the prosecutor is allowed to present. This review is one of the most important things that happens in a DUI defense, and it is impossible to do without actually seeing the evidence.
Why Seeing the Evidence Early Matters
The sooner your attorney has the discovery package, the more options you have. Evidence that needs to be preserved, such as surveillance footage from nearby businesses, can disappear quickly. Witnesses' memories fade. Calibration records get harder to subpoena as time passes. Acting early gives your defense the best chance to identify problems before they become impossible to address. This is general information and not a guarantee of any particular outcome, but I can tell you from experience that the cases where review happens quickly tend to be the cases where the most options remain open.
If you want to understand what the evidence in your specific case actually looks like, I offer a free written case analysis on this page. Call me directly at (888) 271-6644. I answer my own phone, 24/7. You can also read more from the DUI blog for additional guidance on what to expect ahead.