Maryland v. King

Concerning the Constitutionality of Mandatory DNA Collection Pre-Conviction


In a 5-4 opinion authored by Justice Kennedy, the Supreme Court ruled that suspicionless collection of the DNA of those arrested for a serious crime did not violate the Fourth Amendment. The reasonableness of a search is determined by weighing the government’s interest in collection with the degree to which the search intrudes on privacy. The Court found that although swabbing an arrestee's cheek for DNA collection did constitute a search, the minimal physical invasiveness of the collection technique was important in evaluating the reasonableness of the search. Additionally, arrestees enjoy a diminished expectation of privacy. Kennedy found that the government's interest in identifying arrestees, including discovering one’s criminal history, weighed strongly in favor of collecting DNA samples, as this is a highly effective form of identification. The Court analogized to police practices of taking photographs or collecting fingerprints of arrestees, finding that the DNA collection merely served the same function more effectively. Ultimately, the Court weighed what it characterized as a minimal physical intrusion against the potential of DNA to provide law enforcement with valuable information about arrestees, concluding that DNA collection was a reasonable Fourth Amendment search.

Justice Scalia's four-Justice dissent argued that the Fourth Amendment categorically forbids suspicionless searches justified only by the government's interest in detecting crime. Scalia challenged the majority's assertion that the government’s interest in collection was identification of arrestees, arguing instead that the DNA collection was meant to detect crimes. Such a purpose made the search the type of indiscriminate, general search that the Fourth Amendment was meant to protect against.

Top News

  • EPIC Obtains Documents on Secret DNA Forensic Source Code: In response to EPIC's state public records requests, Virginia and Pennsylvania have both released documents about "TrueAllele," a proprietary technique used in DNA forensic analysis. Virginia released to EPIC a validation study and validation summary prepared by the Virginia Department of Forensic Science. Pennsylvania produced purchase and service contracts, technical specifications, and user manuals for TrueAllele. Agencies in California, Louisiana, Pennsylvania, and Virginia have stated that they do not have access to the TrueAllele source code that they are using to produce evidence against defendants. EPIC's open government requests cited the importance of algorithmic transparency in the criminal justice system. (Nov. 10, 2015)
  • EPIC Pursues Public Release of Secret DNA Forensic Source Code: EPIC has filed public records requests in six states to obtain the source code of "TrueAllele," a software product used in DNA forensic analysis. According to recent news reports, law enforcement officials use TrueAllele test results to establish guilt, but individuals accused of crimes are denied access to the source code that produces the results. A similar program used by New Zealand prosecutors was recently found to have a coding error that provided incorrect results in 60 cases, including a high-profile murder case. EPIC has previously urged the US Supreme Court to carefully consider the reliability of new investigative techniques and argued a federal appeals case against DNA dragnet surveillance. Citing the importance of algorithmic transparency in the criminal justice system, EPIC filed requests in California, Louisiana, New York, Ohio, Pennsylvania, and Virginia. (Oct. 14, 2015)
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  • California Court Strikes Down DNA Collection Law: A state appeals court in California has struck down a state law that requires collection of DNA from people arrested on felony charges. The California court ruled that DNA collection by a cheek swab is an unreasonable search and seizure prohibited by the state's constitution. "The California DNA Act intrudes too quickly and too deeply into the privacy interests of arrestees," wrote the court. The appeals court also said that the U.S. Supreme Court's ruling in Maryland v. King, which upheld a similar law in Maryland, did not apply in this case because of significant differences between each state's DNA collection laws. EPIC has participated as amicus in several cases concerning the collection of DNA. In Maryland v. King, EPIC argued that the government collection of DNA opens the door to misuse and threatens personal privacy. For more information, see EPIC: Maryland v. King, EPIC: Maryland v. Raines, EPIC: Kohler v Englade, EPIC: US v. Kincade, EPIC: Herring v. US, EPIC: Comments on TSA Biometric Systems, and EPIC: Genetic Privacy. (Dec. 4, 2014)
  • Supreme Court Allows Warrantless Search of Home: In a case that narrows the warrant requirement for searches of homes, the Supreme Court upheld the warrantless search of a suspect's home by the LAPD after the person objected. In Fernandez v. California, the officers returned to the apartment of the resident after he had been arrested, and obtained consent from a roommate to conduct a search. Justice Alito, writing for the 6-3 majority, found that the roommate's consent was sufficient once the defendant was no longer present. Justice Ginsburg, writing in a dissent joined by Justices Sotomayor and Kagan, argued that the decision "tells the police they may dodge" the warrant requirement and is contrary to a prior a decision of the Court. In Georgia v. Randolph, the Supreme Court previously ruled that when one occupant refuses to consent to a search, the other's consent is not sufficient to permit a search. EPIC has previously filed amicus briefs in a number of important Supreme Court Fourth Amendment cases. For more information, see EPIC: United States v. Jones, EPIC: Maryland v. King, EPIC: Amicus Curiae Briefs. (Feb. 26, 2014)
  • National Institutes of Health Protects Genetic Privacy of HeLa Cells: The National Institutes of Health has agreed to safeguard Henrietta Lacks's family genetic privacy while still allowing research on the famous HeLa cells. During her fight against an aggressive form of cervical cancer in the 1950s, Henrietta Lacks's cells were given to scientists, without her consent, for experimentation because of their ability to replicate in a lab setting. Her cells are still used today for scientific research. EPIC previously submitted comments to the Department of Health and Human Services and argued for stronger privacy protections for genetic data. More recently, EPIC filed a friend of the court brief with the Supreme Court in Maryland v. King arguing for limited law enforcement access to DNA. For more information, see EPIC: Maryland v. King and EPIC: Genetic Privacy. (Aug. 12, 2013)
  • Supreme Court Rules Against DNA Privacy: A deeply divided Supreme Court ruled Monday that law enforcement may warrantlessly collect DNA samples from people arrested, but not yet convicted, of crimes. In Maryland v. King, the Court held that when the police have probable cause to arrest someone, the collection of DNA is analogous to fingerprinting or photographing. The decision was 5-4. Writing in dissent, Justice Scalia, joined by Justice Ginsburg, Kagan, and Sotomayor, stated "Make no mistake about it: . . . your DNA can be taken and entered into a national database if you are ever arrested, rightly or wrongly, and for whatever reason." EPIC wrote a "friend of the court" brief arguing against warrantless DNA searches. EPIC's brief described the rapid expansion of DNA collection in the United States and the lack of sufficient safeguards for private genetic information. For more information, see EPIC: Maryland v. King and EPIC: Genetic Privacy. (Jun. 3, 2013)
  • Supreme Court to Hear Arguments On Warrantless DNA Collection: Today the U.S. Supreme Court will arguments on whether the Fourth Amendment allows warrantless, suspicion less DNA collection from anyone arrested, but not convicted, of a "serious crime." In Maryland v. King, Maryland will argue that states should be permitted to use DNA to investigate cold cases even when the arrestee is not a suspect. King will explain that the Fourth Amendment requires a probable cause warrant for routine law enforcement investigations. EPIC filed a "friend of the court" brief, joined by the 27 technical experts and legal scholars, that describes how DNA collection and use "has grown dramatically and unpredictably over time." EPIC has asked the U.S. Supreme Court to affirm the decision of the Maryland Supreme Court, which held that a warrant is required for the collection of a DNA sample. For more information, see EPIC: Maryland v. King and EPIC: Genetic Privacy. (Feb. 26, 2013)
  • EPIC Urges Supreme Court to Protect Genetic Privacy: EPIC has filed a "friend of the court" brief in Maryland v. King, arguing that law enforcement's warrantless collection of DNA is unconstitutional. EPIC's brief describes the "dramatic and unpredictable" expansion of the government's DNA collection over the past decade. In the brief for the U.S. Supreme Court, EPIC said that the Fourth Amendment limits "the otherwise unbounded collection and use of the individual's DNA sample by government." The EPIC brief was joined by 26 technical experts and legal scholars.EPIC has previously filed amicus briefs in several DNA cases before federal and state courts. For more information, see EPIC: Maryland v. King and EPIC: Genetic Privacy. (Feb. 4, 2013)
  • New Study Finds Limits in Deidentification of DNA Samples: A recent paper published in Science reveals that deidentified DNA sequences collected for research purposes can be used to identify the subjects under certain circumstances. According to the article, the information posted by the 1,000 Genomes Project - age, state of residence, and full DNA sequence - used in combination with publicly available genealogy data was enough to narrow the search to a few likely individuals. A Science Policy Forum article concludes that this "reveals the need to re-examine the current paradigms for managing the potential identifiability of genomic and other 'omic'-type data." The President's Commission for the Study of Bioethical Issues recently reviewed the ethical and privacy implications of the use and collection of genetic data. And the Supreme Court is set to hear a case next month involving the warrantless collection and use of genetic information by law enforcement agencies. For more information, see EPIC: Maryland v. King and EPIC: Genetic Privacy. (Jan. 17, 2013)

Questions Presented

  • Whether the Fourth Amendment allows the states to collect and analyze DNA from people arrested and charged with serious crimes.


The Maryland Supreme Court recently considered the constitutionality of certain portions of Maryland's DNA Collection Act, amended in 2008, which allows collection of DNA samples from "individuals arrested for crimes (or attempted crimes) of violence or burglary prior to being found guilty or pleading guilty." King v. State of Maryland, 42 A.3d 549 (Md. 2012). The court in King held that the warrantless collection of defendant Alonzo King's DNA upon his arrest violated the Fourth Amendment. The U.S. Supreme Court then granted certiorari to hear the case.

Factual Background

Alonzo King was arrested in Maryland for assault in April 2009. At the time of his arrest, pursuant to the Maryland DNA Collection Act, police collected a DNA sample from him using a cheek swab. The Act requires law enforcement to collect DNA samples from all individuals arrested for violent crimes. This sample was processed and profiled, then entered into a law enforcement database and compared to DNA profiles from unsolved "cold" cases. King's DNA matched a sample gathered from an unsolved sexual assault in 2003.

With a "hit" from the DNA database as the sole piece of probable cause against King, a grand jury indicted him on ten charges, including rape. The police obtained a search warrant to collect a second DNA sample, via buccal swab, from King to investigate these new charges. The second buccal swab also matched the DNA sample taken from the sexual assault. This new evidence ultimately led to King being convicted of rape and sentenced to life without parole.

The Maryland DNA Act

The Maryland DNA Collection Act was originally enacted in 1994. It authorized the collection of DNA in order to "assist an official investigation of a crime; to identify human remains; to identify missing persons;" and other purposes. In 2008, the Act was amended to allow the State to collect DNA from people arrested for burglary, or violent crimes, at the time of their arrest.

Law enforcement takes the DNA sample from the arrestee, analyzes it, and the resulting profile is entered into the FBI's CODIS database. When DNA is analyzed under the Act, law enforcement specifically targets thirteen sections, or "loci," known as "non-coding" DNA. If the profile creates any "hits" to open cases, this creates probable cause to obtain a warrant for a second DNA sample from the suspect. Only this second sample is admissible as evidence at trial.

The Maryland Supreme Court's Decision

At his sexual assault and rape trial, the court denied King's motion to suppress the DNA evidence. King pled not guilty to the charges in order to preserve his constitutional challenge to the DNA collection. King appealed his conviction to the Maryland Supreme Court, alleging that the warrantless DNA collection was a violation of his Fourth Amendment rights and that the Maryland DNA act was unconstitutional.

The Maryland Supreme Court, after reviewing many similar cases from other jurisdictions, concluded that the DNA Act was unconstitutional as applied in King's case. To reach this conclusion, the court applied the "totality of the circumstances" test laid out by the U.S. Supreme Court in United States v. Knights. That test requires weighing the intrusion upon individual privacy versus the promotion of a legitimate government interest.

The court said that arrestees, unlike convicts or parolees, have strong privacy rights because they are still cloaked with the presumption of innocence until they are found guilty of a crime. "King, as an arrestee, had an expectation of privacy to be free from warrantless searches of his biological material and all of the information contained within that material." The court stated that DNA is fundamentally different from other biological materials. "A DNA sample, obtained through a buccal swab, contains within it unarguably much more than a person's identity. Although the Maryland DNA Collection Act restricts the DNA profile to identifying information only, we can not turn a blind eye to the vast genetic treasure map that remains in the DNA sample retained by the State."

Meanwhile, the interest asserted by the State in this case was weakly attenuated to DNA collection. The State argued that the DNA act sought to further the identification of arrestees. The court disagreed with this argument, noting that DNA analysis is slow, whereas fingerprinting and photographs are much more efficient identification mechanisms. The real purpose of DNA collection, concluded the court, is to further investigation of unsolved crimes.

"Although we have recognized (and no one can reasonably deny) that solving cold cases is a legitimate government interest, a warrantless, suspicionless search can not be upheld by a 'generalized interest' in solving crimes." The court held that the DNA act was therefore unconstitutional as applied to King and reversed the decision of the lower court.

At The U.S. Supreme Court

The State filed a motion with the U.S. Supreme Court to stay the decision pending petition for certiorari. Chief Justice Roberts, applying the Conkright test, granted the stay. "Collecting DNA from individuals arrested for violent felonies provides a valuable tool for investigating unsolved crimes and thereby helping to remove violent offenders from the general population." Chief Justice Roberts noted that the Maryland Supreme Court decision also lessens the effectiveness of law enforcement in other jurisdictions because it removes potential Maryland offenders from the FBI CODIS database. On November 9, 2012, the U.S. Supreme Court granted certiorari to hear the State of Maryland's appeal.

The Question Presented is: "Does the Fourth Amendment allow the States to collect and analyze DNA from people arrested and charged with serious crimes?"

EPIC's Interest in Maryland v. King

EPIC has a longstanding interest in personal privacy, limiting the government's collection of personal information, and restricting the collection of genetic material. Unlike other biometric data, DNA is more than just an identifier. It is a comprehensive descriptor of all of a person's physical traits and their genealogy. Such valuable personal information must be tightly guarded and restricted to safe, necessary uses. Law enforcement collects and retains complete DNA samples, even though only a few sections are used to create CODIS profiles. There is no statute requiring the federal government to discard the full DNA sample. As genetics researchers discover new ways to use DNA, the potential for misuse by government increases and threatens individual privacy.

When a law enforcement entity collects a DNA sample, the government indefinitely retains that person's full genetic makeup. There is no statute requiring the federal government to discard the full DNA sample. As genetics researchers discover new ways to use DNA, the potential for misuse by government increases and threatens individual privacy. EPIC seeks prevent invasive uses of DNA cataloguing.

EPIC is particularly concerned with the continued expansion of DNA collection from increasingly larger populations; the CODIS database, which once contained only DNA profiles of sex offenders, has expanded to apply to other convicts and parolees. In 2008, the U.S. Attorney General promulgated a regulation that mandated the collection of a DNA sample from every person arrested under federal authority. 28 C.F.R. ยง 28.12(b). All law enforcement agencies in the country, federal, state and local, have access to CODIS. As CODIS expands, individual privacy rights are implicated, and not just for the individual whose DNA is added to the database; the ability to search for partial matches also implicates the privacy rights of family members whose DNA is a close enough match that the person is flagged in a CODIS DNA search.

Past EPIC "Friend of the Court" Briefs on DNA privacy and law enforcement databases

In 2004, EPIC submitted a 'friend of the court' brief in Maryland v. Raines, 857 A.2d 19 (Md. 2004). This case, a precursor to Maryland v. King, also dealt with a constitutional challenge to Maryland's DNA act. Charles Raines, an incarcerated felon, was forced to submit to a DNA test, which ultimately linked him to an unsolved sexual assault. EPIC argued that the DNA Collection Act violated both the Fourth Amendment and Article 26 of the Maryland Declaration of Rights, Maryland's state constitutional equivalent. The Maryland Court of Appeals held that the Act did not violate Raines's rights because he, as an incarcerated individual, 'enjoy[ed] less liberty than that of ordinary citizens.'

In 2005, EPIC filed a 'friend of the court' brief (PDF) in Kohler v. Englade, 470 F.3d 1104 (5th Cir. 2006), where police in Baton Rouge, Louisiana conducted a house-to-house dragnet to collect DNA samples. EPIC successfully helped affirm that such practices are illegal.

In 2004, EPIC filed a "friend of the court" brief (PDF) in United States v. Kincade, 379 F. 3d 813 (9th Cir. 2004). This case addressed the DNA Analysis Backlog Elimination Act's compulsory DNA collection from parolees. EPIC argued that the statute was unconstitutional under the Fourth Amendment. The court held that an individual already convicted had a lowered expectation of privacy, allowing the DNA collection.

In 2009, EPIC filed a 'friend of the court' brief (PDF) in Herring v. United States, 555 U.S. 135 (2009). In that case, the Supreme Court considered the constitutionality of a police search premised on erroneous information from an inaccurate law enforcement database. EPIC argued that the dramatic expansion of law enforcement databases riddled with inaccuracies and incomplete information puts individuals at risk and jeopardizes criminal investigations. The Court held that the Fourth Amendment only requires the suppression of evidence when doing so would meaningfully deter similar behavior in the future, and when police conduct was sufficiently culpable that such deterrence is worth the price paid by the justice system. Although the Court majority did not exclude the evidence, Justice Ginsburg, writing for four of the Justices in dissent, said that "negligent record-keeping errors by law enforcement threaten individual liberty, are susceptible to deterrence by the exclusionary rule, and cannot be remedied effectively through other means."

In 2005, EPIC submitted administrative comments to the TSA regarding the use of biometric data in access control systems used by workers at the nation's airports. EPIC cited a number of ways in which such biometric systems can be easily defeated, such as by using false identification at enrollment, physical alteration of a personal biometric, skewing sample collection by not cooperating, and hacking into or falsifying the database.

Legal Documents

United States Supreme Court

Maryland Court of Appeals


Relevant Precedent

  • Supreme Court and Appellate Court Cases
    • Maryland v. Raines, 857 A.2d 19 (Md. 2004)
    • People v. Buza, 129 Cal.Rptr.3d 753 (Cal.Ct.App. 2011)
    • Florence v. Board of Chosen Freeholders of Cnty. of Burlington, 132 S. Ct. 1816 (2012)
    • Samson v. California, 547 U.S. 843 (2006)
    • United States v. Knights, 534 U.S. 112 (2001)
    • United States v. Mitchell, 652 F.3d 387 (3d Cir. 2011) (en banc)
    • Haskell v. Harris, 669 F.3d 1049 (9th Cir. 2012), pet'n for reh'g pending.
    • Mario W. v. Kaipio, 281 P.3d 476 (AZ S.Ct. 2012).
    • Schmerber v. California, 384 U.S. 757 (1966)

Relevant Law Review Articles, Reports, and Books

  • Presidential Commission for the Study of Bioethical Issues, Privacy and Progress in Whole Genome Sequencing (Oct. 2012).
  • Anita Allen, Privacy and Medicine, Stanford Encyclopedia of Philosophy (2009).
  • Helen Nissenbaum, Personal Data: the Logic of Privacy, The Economist (2007).
  • Latanya Sweeney, Weaving Technology and Policy Together to Maintain Confidentiality, National Commission on Vital and Health Statistics (1998).
  • Emily C. Barbour, Cong. Research Serv., RL 41847, DNA Databanking: Selected Fourth Amendment Issues and Analysis (2011)
  • Mary McCarthy, Am I My Brother's Keeper?: Familial DNA Searches in the Twenty-First Century, 86 Notre Dame Law Review (2011)
  • Andrea Roth, Safety in Numbers? Deciding When DNA Alone is Enough to Convict, 85 New York University Law Review 1130 (2010)
  • Candice Roman-Santos, Concerns Associated with Expanding DNA Database, 2 Hastings College & Technology Law Journal 267 (2010)
  • Jessica Gabel, Probable Cause from Probable Bonds: A Genetic Tattle Tale Based on Familial DNA, 21 Hastings College of the Law 3 (2010)
  • The Perils of Suspicionless DNA Extraction of Arrestees Under California Proposition 69: Liability of the California Prosecutor for Fourth Amendment Violation? The Uncertainty Continues in 2010, 37 Western State University Law Review 183 (2010)
  • Michael Seringhaus, The Problem Child: Forensic DNA Databases, Familial Search, and A Call for Reform, Yale Law School Student Scholarship Repository, Student Prize Papers (2010).

News Reports

Print Media


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