The same evidence is read by prosecutors and defense attorneys for different purposes. Why discovery and thorough defense review make the justice system work better for everyone.
Caseprep is built around a simple idea: a case file should be complete, organized and honest about its gaps before it moves forward. That idea is usually discussed from the perspective of investigators and prosecutors preparing a case. But every case file has two sides. The same evidence that investigators gather and prosecutors evaluate is later reviewed by defense attorneys looking for weaknesses, errors and legal issues. That second review is not a flaw in the system. It is a central part of how the system is supposed to work.
This article explains, in general terms, the role of discovery and defense review in criminal cases, using DUI cases as an example. It is educational information only, not legal advice. Rules of discovery and procedure vary by jurisdiction and court.
The adversarial system
The American criminal justice system is adversarial. The prosecution presents evidence that a crime was committed, and the defense tests that evidence. A judge or jury decides. The premise is that truth is more likely to emerge when both sides examine the evidence rigorously. Constitutional protections, including the right to counsel, the right to confront witnesses and the presumption of innocence, are built into this structure.
What discovery is
Discovery is the process by which parties obtain information about the evidence in a case. In criminal cases, the prosecution generally must provide the defense with certain evidence, which may include police reports, witness statements, test results, video recordings and expert reports, depending on the rules in that jurisdiction.
In addition, under United States Supreme Court decisions, prosecutors have a constitutional duty to disclose evidence favorable to the accused that is material to guilt or punishment. This is often referred to as the Brady obligation, after the case that established it.
Discovery in DUI cases
In a DUI case, discovery may include:
- The incident report and supplemental reports
- Dash camera and body camera video
- Breath test site video
- Breath test tickets and instrument records
- Blood test lab reports and chain of custody
- Field sobriety test documentation
- Dispatch records
- Witness information
Some records, like instrument maintenance logs, may need to be requested specifically.
How defense attorneys review a file
A defense attorney reads the file with different questions than an investigator:
- Was there a lawful basis for each step: the stop, the detention, the arrest, the testing?
- Were the person’s rights respected?
- Does the evidence actually prove each element of the charge?
- Are there inconsistencies between reports, video and records?
- Were procedures followed for tests and evidence handling?
- Is anything missing that should be there?
- Is there an innocent explanation for observations?
The defense does not have to prove innocence. It tests whether the prosecution can prove guilt beyond a reasonable doubt and whether the evidence was lawfully obtained.
Why thorough defense review helps everyone
It might seem that defense review only benefits the accused. In practice, it supports the whole system:
- Accuracy: errors in evidence, procedure or identification are more likely to be caught
- Accountability: knowing that work will be scrutinized encourages careful investigation and documentation
- Legitimacy: outcomes are more trustworthy when evidence has been tested
- Protection of rights: constitutional protections only work if someone checks whether they were followed
The investigator’s perspective
For investigators, anticipating defense review is part of good case preparation. Asking “how would the defense read this?” before a file goes to the prosecutor helps identify gaps that can still be addressed, inconsistencies that need explanation and evidence that needs to be documented more clearly. The best case files are built with both readers in mind.
The role of technology
As evidence volumes grow, especially with video, both sides face the challenge of reviewing large amounts of material thoroughly. Case preparation tools can help organize evidence, build timelines and flag gaps. Defense attorneys increasingly use similar tools. In both cases, human judgment remains essential, and tools that summarize or analyze evidence must be checked carefully against the source material.
When defense review finds problems
If defense review identifies legal problems, the defense may file motions asking the court to suppress evidence or dismiss charges. If it identifies weaknesses in the evidence, these may be addressed through negotiation or at trial. If it finds that the evidence is strong, the defense may advise the client about options accordingly. In every scenario, the review informs better decisions.
Common questions
Does the defense have to share its evidence?
Discovery obligations on the defense side exist in some circumstances, depending on the jurisdiction’s rules, but they are generally more limited than the prosecution’s.
What if evidence is missing?
Missing evidence can raise questions about why, and depending on the circumstances and law, may lead to legal arguments.
Why does defense review take time?
Thorough review of reports, hours of video, records and law takes time. Rushing increases the chance of missing something important.
A DUI example from both sides
Consider a fictional DUI file. The report says the driver weaved across the lane line twice, smelled of alcohol, had glassy eyes and showed four clues on the walk-and-turn. A breath test produced a result above the legal limit about an hour after the stop.
An investigator preparing the file asks: is each observation documented clearly? Is the video complete? Were the implied consent advisements recorded? Is the instrument record in the file? Are there gaps a prosecutor will notice?
A defense attorney reviewing the same file asks: does the dash camera actually show the weaving? Was the shoulder where the walk-and-turn was given sloped or sandy? Were the instructions complete? Was the observation period before the breath test properly followed? Was the instrument maintained as required? Do the times in the report match the video?
Both sets of questions are legitimate, and both make the file more reliable. If the investigator has already asked the defense attorney’s questions, the answers are in the file, and the case can be evaluated on its real strengths and weaknesses.
Exculpatory evidence and the duty to disclose
Prosecutors’ obligations to disclose favorable evidence extend to information known to the investigating agency, which is why investigators play an important role in making sure such information reaches the prosecutor. In practice, this means documenting everything relevant, including details that do not fit the theory of the case, and passing it along. A complete file protects the integrity of the prosecution as well as the rights of the accused.
Defense investigation
Defense teams sometimes conduct their own investigation: visiting the scene, photographing conditions, interviewing witnesses, obtaining records from businesses and consulting experts. This independent work can uncover information that was never in the official file. Defense investigators follow ethical rules and legal requirements in doing so.
Respect on both sides
The adversarial system works best when each side respects the other’s role. Investigators and prosecutors who understand why defense review matters tend to build better files. Defense attorneys who understand the pressures on investigators can focus their review on what genuinely matters. Both sides share an interest in accurate evidence and fair outcomes, even when they disagree about what the evidence shows.
What this means for people charged
For a person charged with a crime, the key point is that the file prepared by law enforcement is not the final word. It is evidence to be examined. Having a lawyer who reviews that evidence carefully, asks the right questions and understands the applicable law is one of the most important protections available.
When files are incomplete
Sometimes the most important discovery in a defense review is what is not there: a missing video segment, an absent maintenance record, an unnamed witness mentioned in passing or a report written days after the event. Incompleteness does not automatically mean anything improper happened. Equipment fails and records are misplaced. But it does raise questions that should be asked and answered, because a decision based on an incomplete file is a decision made without all the facts.
The value of a second read
Anyone who has proofread their own writing knows how easy it is to miss errors in work you already understand. Case files are no different. The person who built a file knows what it is supposed to say, which makes gaps and contradictions harder to see. A second reader with a different purpose, whether a supervisor, a prosecutor or a defense attorney, brings fresh eyes and a different set of questions, and that difference is precisely what makes review valuable.
Inviting that second read early, rather than waiting for it to happen in court, is one of the simplest ways any case team can improve the quality of its work.
Defense review in Grand Strand DUI cases
In a DUI case from Myrtle Beach or elsewhere in Horry County, the defense review of video, breath test records, field sobriety test administration and South Carolina’s specific procedural requirements can make a meaningful difference. Anyone charged with DUI in the area can speak with Johnny Gardner, a Grand Strand DUI lawyer, about having the evidence in their file reviewed carefully under South Carolina law. This article is general information and not legal advice.
This article is general educational information about legal processes, not legal advice. DUI laws and procedures vary and change. If you are facing a charge or a license suspension, speak with a licensed South Carolina attorney promptly.