Why a Warrant Isn’t Always the End of the Road

DWI Attorney North Texas
In modern North Texas DWI enforcement, the “No Refusal” policy is often the standard, not the exception. If you refuse to provide a breath or blood sample voluntarily, officers will likely apply for a Blood Search Warrant. While this may feel like an airtight process, a warrant is only as strong as the “four corners” of the document it’s written on.
At Beltz Law Group, we meticulously dissect every warrant to ensure your Fourth Amendment rights were not bypassed in the rush to gather evidence.
How a Blood Warrant is Obtained
Under Texas Code of Criminal Procedure Article 18.02(10), blood is considered “evidence” of a crime. To seize it against your will, an officer must follow a specific legal path:
- The Sworn Affidavit: The officer must draft a written statement (the affidavit) detailing the probable cause that justifies the search. This includes observations of slurred speech, the smell of alcohol, or poor performance on field sobriety tests.
- The Neutral Magistrate: The affidavit is sent to a judge (magistrate). The judge must review the facts and agree that there is a “fair probability” that evidence of intoxication will be found in your blood.
- The Warrant Execution: Once signed, the warrant commands a qualified professional (like a phlebotomist or nurse) to draw your blood in a “medically acceptable manner.”
Common Grounds for Challenging a Warrant
Just because a judge signed a piece of paper doesn’t mean the evidence is admissible. We look for “cracks” in the warrant process, such as:
1. Lack of Probable Cause (The “Four Corners” Rule)

Texas DWI Defense Attorney
In Texas, a court can only look at what is written inside the affidavit. If the officer forgot to mention that you were driving or didn’t provide specific signs of intoxication, the warrant may be legally “insufficient.” If the affidavit is mostly “boilerplate” language without specific facts about your case, we can file a Motion to Suppress.
2. The “Stale” Evidence Problem
Alcohol metabolizes over time. If there was a significant, unexplained delay between the time you were driving and the time the warrant was issued, the probable cause may have gone “stale.” A warrant issued four hours after a stop might not legally justify the seizure of blood that no longer reflects your state while behind the wheel.
3. Improper Administration of the Oath
An affidavit must be sworn under oath. In the age of “e-warrants,” officers sometimes skip the formal oath-taking process with the judge. If the officer signed the document but wasn’t properly sworn in—either in person or via a reliable electronic method—the entire warrant could be ruled defective.
The Testing is a “Second Search”
A landmark shift in Texas law (the Crider and Martinez cases) established that the drawing of blood and the testing of blood are actually two separate events. While a standard DWI warrant usually covers both, we verify that the laboratory analysis didn’t exceed the scope authorized by the judge.
What Happens if the Warrant is Thrown Out?
If we successfully challenge a warrant through a Motion to Suppress, the blood test results are “excluded” from your trial. Without that BAC number, the prosecution’s case often crumbles, leading to:
- A reduction of charges (e.g., from DWI to Obstruction of a Highway).
- A complete dismissal of the case.
- Significant leverage during plea negotiations.
Was your blood taken against your will? A warrant is a powerful tool for the State, but it must be executed perfectly to stand up in court. At Beltz Law Group, we have the experience to spot the errors that others might miss.




