Records & Discovery: The Paper Trail That Wins DUIs
The evidence that beats a DUI is often not at the scene, it’s in the calibration history, maintenance logs, and lab records the State would rather you never see. Getting them is a fight, and it is one we know how to win.
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What records can prove a DUI machine was unreliable?
Quick answer: The machine’s calibration and accuracy-check records, maintenance and repair logs, operator certifications, and the lab’s gas-chromatography data and quality-control records. These documents often reveal a machine that was out of tolerance, recently repaired, or improperly serviced, and the State does not hand them over unless forced through aggressive discovery.
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Former Prosecutors · Law Enforcement · Public Defenders
When you call Tamou Law Group, you reach a firm that handles criminal defense exclusively, with serious experience defending DUI cases across Arizona. Our team includes former prosecutors and law enforcement officers, so we know exactly how the State builds these cases, and where they fall apart.
At many large firms, the name on the building is a marketing figurehead, you rarely get them on the phone and your case goes to a junior associate. When you hire Tamou Law Group, your case is handled by a full team of attorneys, not associates, including Michael Tamou.
Cases Are Won in the Records
The police report is the State’s story. The records tell the real one.
A DUI defense is only as good as the evidence behind it, and the most powerful evidence is documentary: the machine’s history and the lab’s data. A breath or blood challenge (see our breath and blood guides) lives or dies on these records.
The Discovery We Force the State to Produce
We know exactly what to request, and how to compel it when they resist.
Through targeted discovery requests and, when necessary, motions to compel, we pursue:
- Calibration & accuracy-check records for the specific machine, before and after your test.
- Maintenance, service, and repair logs, evidence the machine was malfunctioning or recently fixed.
- Operator/instrument certifications and training records.
- Lab data packets, the gas-chromatography runs, calibration, controls, and quality-control records.
- Officer records, body-cam, dash-cam, and the 15-minute observation documentation.
- Historical error data for the same machine across other cases.
The State often produces a summary and hopes that satisfies. It does not, we press for the underlying data where the problems live.
When They Won’t Produce: Motions & Sanctions
Withheld evidence is its own defense.
When the State stonewalls, we file motions to compel and, where evidence was lost or destroyed, motions for sanctions or dismissal. Failure to preserve or produce key records can result in the evidence being excluded, or the case being dismissed outright.
Deadlines matter, and so does knowing what to ask for. This is routine, technical work that many lawyers skip, and it is exactly where cases are won.
The Records That Win DUIs
The evidence that beats a DUI is usually documentary. Here is what we demand, and what it reveals.
Records We Request in Every Case
- Calibration & accuracy-check logs before and after your test.
- Maintenance, service, and repair history for the specific machine.
- Quality-assurance (QAS) records and operator certifications.
- The lab’s full gas-chromatography data packet and quality-control records.
- Body-cam, dash-cam, and the 15-minute observation log.
- Historical error data for the same machine in other cases.
Why It Matters
- An out-of-tolerance calibration can make the result inadmissible.
- A machine repaired near your test date is suspect.
- Lost or withheld records can lead to suppression or dismissal via motions and sanctions.
- Some video and logs are overwritten on short cycles, so we send preservation demands immediately.
The Paper Trail That Ends the Case
The right document can end a DUI before trial.
A single out-of-tolerance calibration or a missing maintenance record can render the State’s number inadmissible. Combined with the scientific challenges, disciplined discovery produces suppression, reductions, dismissals, and acquittals.
Part of a full defense, see the Top 10 DUI defenses and Phoenix DUI defense. Call 623-321-4699, 24/7.
The Experts We Bring to DUI Cases
A DUI is a science case. We bring the specialists who take the State’s numbers apart, click any to see how.
Forensic Toxicologists
BAC & Absorption
Independently review the blood and breath results, the absorption curve, and whether the alleged number reflects your true level at the time of driving.
Breath-Test Analysts
Intoxilyzer & Calibration
Examine the machine’s calibration and maintenance logs and the 15-minute observation, exposing mouth alcohol, radio interference, and operator error that inflate readings.
Blood & Lab Experts
Gas Chromatography
Audit the blood draw, storage, fermentation risk, lab protocol, and reported uncertainty, where applying the margin of error can drop the reading below the threshold.
Medical Experts
GERD, Diabetes & Diet
Explain how acid reflux, diabetes, and low-carb diets can push a breath reading upward, independent of how much alcohol was actually consumed.
Field Sobriety Experts
NHTSA Protocol
Evaluate whether the standardized field sobriety tests were administered and scored correctly, and whether the “clues” really show impairment.
Records & Discovery Specialists
Maintenance & Logs
Pull the full calibration history, repair records, and the discovery the State would rather not produce, the paper trail that often reveals an unreliable machine.
Awards & Recognition
Our recognition for Phoenix DUI defense is independently verified, click any award to confirm it:
- National Trial Lawyers Top 100
- National Trial Lawyers Top 40 Under 40
- Elite Lawyer 2026 – Criminal Defense
- Super Lawyers – Southwest
- National College for DUI Defense (NCDD)
Together, these place Tamou Law Group among the best Phoenix DUI lawyers, led by Founding Attorney Michael Tamou and a full team of attorneys, including former prosecutors.
Phoenix DUI Defense FAQs
Quick answers to the questions we hear most.
What records should my DUI lawyer request?
Calibration and accuracy-check records, maintenance and repair logs, operator certifications, the lab’s gas-chromatography data and quality-control records, body/dash-cam, and the machine’s historical error data. These reveal an unreliable machine or analysis.
Can a DUI be dismissed over missing records?
Yes. If the State fails to preserve or produce key evidence like calibration or maintenance logs, courts can exclude the result or dismiss the case through motions to compel and sanctions.
Why do calibration and maintenance logs matter?
They show whether the machine was accurate and properly serviced around your test. An out-of-tolerance calibration or a machine repaired near your test date makes the result unreliable.
Does the State hand over all the evidence automatically?
No. It typically produces a summary result and withholds the underlying data. Getting the full calibration history and lab data packet usually requires aggressive, specific discovery requests.
How long do I have to preserve evidence in my DUI case?
Act quickly, some records and video are overwritten on short cycles. Early counsel means preservation letters and discovery go out before key evidence disappears. Call 623-321-4699, 24/7.
Key Takeaways
- The evidence that beats a DUI is usually documentary, not at the scene.
- Calibration history, maintenance/repair logs, and lab data packets expose unreliable machines.
- The State produces summaries and withholds the underlying data unless compelled.
- Lost or withheld records can lead to excluded evidence or dismissal via motions and sanctions.
- Records must be requested fast before they are overwritten. Call 623-321-4699, 24/7.
What Clients Say About Tamou Law
Real Google reviews from clients we have defended across Phoenix and Maricopa County. Every review is from a criminal defense client, never padded with non-legal work.
Two Arizona Offices, One Team
We serve all of Maricopa County and the surrounding area, with free, confidential consultations 24/7 by phone and in-person meetings at either office by appointment.
Case Results Disclaimer: The results described on this page are based on specific facts and circumstances and do not guarantee or predict a similar outcome in any future case. Every case is different. Past results do not guarantee future results. No attorney-client relationship is formed by viewing this page or submitting a contact form until a written fee agreement has been signed. Tamou Law Group, PLLC is licensed to practice law in the State of Arizona. This website is for informational purposes only and does not constitute legal advice.