What evidence supports probable cause for blood draw warrants in DUI cases? State v. Walker Explained

In State v. Walker, the Utah Supreme Court addressed whether a magistrate had probable cause to issue a warrant authorizing police to draw blood from a defendant involved in a fatal car accident. The case provides important guidance on what circumstantial evidence can establish probable cause in DUI investigations.

Background and Facts

Walker was driving south when her vehicle crossed the center line for an “unknown reason” and struck two northbound vehicles. One driver died at the scene, and another was seriously injured. When detectives interviewed Walker at the hospital, she declined to submit to a blood draw and claimed she didn’t remember anything about the crash. A records check revealed her driver’s license was revoked for alcohol violations and she was restricted to vehicles with interlock devices. However, she was driving her boss’s vehicle at the time of the accident.

Key Legal Issues

The central issue was whether the affidavit submitted to the magistrate contained sufficient facts to establish probable cause for the blood draw warrant. The trial court initially found the warrant lacked probable cause but denied Walker’s suppression motion based on the good faith exception to the exclusionary rule.

Court’s Analysis and Holding

The Utah Supreme Court applied the substantial basis test, reviewing whether the magistrate had a substantial basis to believe evidence of a crime would be found in Walker’s blood. The court emphasized that magistrates’ probable cause determinations receive great deference and must be viewed in a “practical, commonsense fashion.”

The court found several facts, when considered together, supported probable cause: (1) Walker’s vehicle crossed the center line for an unknown reason; (2) she couldn’t remember the accident details; (3) her license was revoked for alcohol violations; (4) she was restricted to interlock devices; and (5) she was driving a vehicle without an interlock device. The court noted that while Walker’s driving history alone might not support probable cause, the combination of all these circumstances provided a substantial basis for the magistrate’s determination.

Practice Implications

This decision demonstrates that courts will consider the totality of circumstances when evaluating probable cause for search warrants in DUI cases. Defense practitioners should carefully scrutinize affidavits to ensure they contain specific, articulable facts rather than mere conclusions. The court’s emphasis on reviewing affidavits in a “commonsense fashion” suggests that seemingly innocent explanations for suspicious behavior may not defeat probable cause when viewed alongside other incriminating circumstances.