State v. Mitcham: Fourth Amendment Protections Concerning DNA Profiling

By Molly Woodward. 

The Fourth Amendment protects “[t]he right of the people to be secure in their persons, houses, papers, and effects against unreasonable searches and seizures.” Though traditionally related to common-law trespasses, the Supreme Court of the United States has made it clear that what the Fourth Amendment truly protects is “people, not places.” 

In December of 2024, the Arizona Supreme Court issued its State v. Mitcham opinion, furthering the Fourth Amendment’s protection of people. The unanimous opinion specifically addressed “whether the sequencing of [a defendant’s] DNA profile from [a] second vial of blood taken during [a] DUI arrest constituted a search,” and ultimately concluded it was an unconstitutional search under the Fourth Amendment.

The Facts Leading to State v. Mitcham

In 2015, Ian Mitcham was arrested by Scottsdale Police for DUI. Mitcham was advised that, pursuant to Arizona law, his failure to consent to blood testing would suspend his driver’s license for a year. Mitcham gave consent, and two vials of blood were drawn. The first vial was tested by the officers for alcohol concentration and drug content while the second vial was offered to Mitcham for his independent testing. Mitcham did not conduct an independent test, however. Instead he signed a “Destruction Notice.” This “Destruction Notice” acknowledged that, unless Mitcham asked for it within ninety days, police would destroy the second blood vial. Mitcham never requested the second vial but the police never destroyed it. Mitcham was ultimately convicted of his DUI. 

A month after Mitcham was arrested for his DUI, Allison Feldman was found murdered in Scottsdale. Biological swabs were collected from the scene and subsequently used to develop a male DNA profile, which was added to the National DNA Index System (NDIS). Two years later, a familial DNA investigation was conducted by police through searching Arizona’s DNA identification system for incarcerated men in Arizona who were likely related to the unknown male profile. Through this search, Mitcham’s incarcerated brother was identified as a close relative to the DNA profile. The search indicated the match was likely related to the incarcerated brother through either a parent-child or sibling relationship. The search process enabled police to narrow their list of prospective suspects to the incarcerated brother’s two sons and three brothers, including Mitcham; however, only Mitcham and one other brother lived in the vicinity of Phoenix. (For another discussion on forensic familial DNA tests and the appellate court’s opinion in this case, see this article.) 

Officers discovered Mitcham’s second blood vial from his 2015 DUI was not destroyed and still in police possession. Without a warrant, police used the second blood vial to create a DNA profile of Mitcham. In 2018, the crime lab found that the unknown DNA profile from Feldman’s murder scene matched Mitcham’s DNA profile created from the second vial. A court-issued warrant was obtained using the DNA profile.

After a series of further searches and seizures—made with the court-issued warrant—Ian Mitcham was arrested, charged, and indicted for the crimes against Feldman. Mitcham sought to suppress all evidence from the second vial. This evidence included the DNA evidence and evidence gathered using the search warrant. The evidentiary suppression requested was in line with the “Fruit of the Poisonous Tree” doctrine: evidence is inadmissible and is excluded from consideration if it derives from illegally obtained evidence, for “if the evidential ‘tree’ is tainted, so is its ‘fruit.’” The trial court granted the motion to suppress but the court of appeals unanimously reversed. The Arizona Supreme Court then took up the issue. 

A Search Was Conducted 

First, the court determined whether using the second blood vial from Mitcham’s DUI to sequence the DNA was a search under the Fourth Amendment. The State argued the DNA sequencing was not a search because the second vial of blood was already lawfully possessed. The court disagreed with this assessment. 

Calling upon their opinion in Mario W. v. Kaipio, the court reiterated the Fourth Amendment protections afforded to criminal defendants despite diminished privacy expectations. A defendant “does not forfeit Fourth Amendment protections with respect to other offenses not charged absent either probable cause or reasonable suspicion.” 

In Mario W., the court indicated a buccal swabbing and subsequent DNA profiling from the buccal sample were two separate intrusions. The DNA profiling was more invasive of privacy than the buccal swab because unique genetic markers would be extracted from the DNA and made into an individually unique DNA profile published nationwide to law enforcement. The State argued that the Supreme Court case, Maryland v. King, overruled Mario W., but the Arizona Supreme Court disagreed. The court indicated that King did not address whether it was a separate search to use the buccal sample to develop a DNA profile. Therefore, King overruled Mario W. only so far as King “held that processing buccal swabs before adjudication violated the juveniles’ Fourth Amendment rights.” 

Therefore, the rule of law regarding DNA profiling in Mario W. endured and “extracting Mitcham’s DNA profile in 2018 from the second vial of blood taken during his 2015 DUI arrest was a ‘search’ under the Fourth Amendment.” 

The Search Was Unreasonable

Next, the court addressed whether the search was unreasonable. As it was a warrantless search, the search was unreasonable unless an exception applied. The court addressed the “free and voluntary consent” exception to a warrantless search. The State argued Mitcham consented to the 2018 search (a.k.a. the DNA profiling) when he consented to the 2015 DUI blood draw. The court applied a reasonable person test to determine whether the State’s argument for the consent exception held weight: “The question before us then is whether a reasonable person would have understood that consenting to a blood draw would have understood that consenting to a blood draw to determine alcohol or blood content would include consent to create a DNA profile form that sample.” 

In applying this test, the court found the “typical reasonable person” standing in Mitcham’s shoes “would not have understood that consenting to the blood draw for the limited purpose of determining alcohol concentration or drug content also included consenting to the creation of a DNA profile, especially years later.” Because the voluntary consent exception does not apply, the warrantless search was held to be unreasonable. In fact, the court “emphatically reject[ed] the State’s position that it was free to analyze Mitcham’s blood in any way it pleased simply because the State lawfully possessed the blood vials.” 

Constitutional Protections and Limitations

Despite holding there was a Fourth Amendment violation, the court determined the inevitable discovery exception applied. Since Mitcham had previously been sentenced to time in the Arizona Department of Corrections, and, there, Arizona law requires a sample of blood for DNA profiling purposes, it was found the police would have inevitably obtained Mitcham’s DNA profile without the unconstitutional search. Thus, the trial court was wrong to suppress Mitcham’s DNA profile. 

Despite the State’s success under the inevitable discovery doctrine, this case can be considered a win for Arizona defendants. State v. Mitcham ensured defendants’ Fourth Amendment rights were protected insofar as preventing officers from abusing defendants’ limited consent to blood draws and tests. Had the court ruled otherwise, lawfully obtained DNA samples could be subject to secondary searches, or more, to the gross violation of the blood contributor’s privacy rights. This ruling protected such individuals from underhanded investigatory techniques. 

It is important to note, however, how this decision still balances the government’s interests. It does so by supporting police officers’ ability to obtain evidence through statutory obligations, such as Arizona’s law requiring convicted individuals to submit blood samples for DNA profiling purposes. 

The Fourth Amendment protects “people, not places.” This Arizona Supreme Court decision supports that creed, for what is more inextricably related to people than their DNA? Than their individualized genetic code? Despite statutory limitations, people’s privacy rights continue to be respected and protected through the court’s determination that DNA sequencing was a search and that the consent exception was inapplicable given the limited scope of the consent provided for the DUI test.