The U.S. Supreme Court case of Birchfield v. North Dakota determined whether a warrant was needed to draw blood in a DUI case. In this case, the Court found that officers do need to obtain a search warrant before subjecting a suspect to a blood test. The Court also added that states cannot criminalize refusing a blood test if no warrant has been obtained. Although Birchfield deals with a DUI case, it created questions about other police investigations where blood testing is sought.