How Do the Police Acquire a Warrant to Draw Blood?

We recently wrote about whether the police need a warrant to obtain a blood sample from you when you are being detained on suspicion of DWI. Since a 2014 decision by the Texas Court of Criminal Appeals, the answer to that question is, “Yes the police must obtain a warrant to take a blood sample unless you consent.”

What goes into getting a search warrant for a blood sample? What do the police need to show? And who makes the decision?

History of Warrantless Searches and Seizures for Blood Samples by Police

Up until a the U.S. Supreme Court decided in 2013, law enforcement across the country routinely took blood samples without search warrants. The operating procedure for some police organizations was to get a blood sample from a suspect of DWI by taking them to a local hospital or jail and having his or her blood drawn.

The thinking at the time was that because alcohol levels dissipate from the bloodstream over time, the need for taking a timely sample to preserve how much alcohol was in the blood was crucial. This was considered an exigent circumstance of disappearing evidence, one of the few exceptions to the general requirement that the police need a warrant to search you or seize your property.

Missouri v. McNeely changed all that. That case involved a DWI suspect that was pulled over and refused to take a breathalyzer and give blood sample. Despite his refusals, the arresting police took him to a hospital and had his blood drawn. He made the argument to the Supreme Court that the Fourth Amendment to the U.S. Constitution prohibits the police from taking blood samples without obtaining a proper search warrant.

Elements to a Proper Search Warrant

The general law of search warrants can be found in Texas Code of Criminal Conduct Chapter 18. There you will find what a search warrant is, who approves it, and what elements must be shown to get a proper search warrant for a blood draw in a DWI case.

The simple definition for a search warrant is an order by a magistrate or judge and given to a law enforcement officer to search or seize the property designed in the order itself. Any warrant should be very specific as to what the police are allowed to search or seize, and the police are not allowed to search or seize more than what the warrant allows. If they do, you could challenge that the terms of the warrant were violated.

Before a warrant can be signed by a judge or magistrate, the police have to show several things. They have to show that the facts of the case indicate there is probable cause that:

  • A specific crime was committed
  • The things to be searched or seized were involved somehow in the alleged offense and would serve as evidence
  • The things to be seized or searched are located in the place to be searched

Each of these things has to be sworn to by a police officer in an affidavit that is submitted to the court. Then the police take the sworn out warrant and go get the blood sample, search the car, or do whatever else the warrant allows them to do.

A DWI Defense Firm to Protect Your Rights

At The Wilder DWI Defense Firm, we defend people charged with DWI in the Dallas area. As our client, you will have all our attention, focus, and talents at your disposal. We fight the police, prosecutors, and defend your case in court even if it means taking your case to trial. If you have been arrested and charged with DWI, contact us. We will evaluate your case for you and give you the advice you need.