By Alyssa Thompson



Since 1997, select states have been collecting DNA samples from particular arrestees.[1] Between 2006 and 2011, twenty-three states passed legislation authorizing this practice.[2] As of 2013, thirty states and the federal government take part in DNA collection of certain arrestees.[3] Around half of the states collecting DNA collect for any felony, while the other half limits collecting from violent felonies or sex crimes.[4] As of 2013, eight states collect for select misdemeanors.[5] Additionally, eight states and the federal government collect from juveniles.[6]

Samples are taken via a buccal swab.[7] This has become a popular method as it is seen as a minimally invasive method of DNA collection.[8] The swab is placed inside the check and obtains DNA in the form of buccal epithelial cells.[9] If an inmate refuses, the federal government instructs testers to use force to obtain the sample.[10] If carried out correctly, buccal swabs are just as accurate as blood tests.[11]

Processed samples are entered into the Combined DNA Index System (“CODIS”), a national database containing samples contributed by federal, state, and local forensic laboratories.[12] According to the FBI, these DNA samples identify offenders, exclude innocent persons, solve past and future crimes and combat recidivism.[13] Further, DNA samples in this context have solved a number of cold cases.[14]

States differ on how they destroy the samples if the charges brought do not lead to conviction.[15] The majority of states only destroy the sample upon request, meaning the individual, against whom charges were brought and subsequently dropped or lead to acquittal or dismissal, must bear the burden of getting the sample expunged.[16] It can cost anywhere from $50 to $500 to expunge a record.[17] In states that require the individual to initiate the expungement process, very few expungements occur.[18] This is likely due to a lack of informing individuals of their right to have their record expunged coupled with the costs of expungement.

Fourth Amendment Concerns

DNA collection is undoubtedly a search. Under the Fourth Amendment there are two contexts in which a search can take place. First there is the investigatory context. Under this context, if there is an objective justification for the action, a law enforcement officer’s subjective intent is not relevant to a court’s inquiry of the matter.[19] The second context is the special needs context. Subjective intent does matter when there is no objective justification for the search. This includes inventory searches and administrative searches. Law enforcement may not use the special needs context as a way to get around the 4th amendment – the search must be for the reason law enforcement purports it to be (i.e., inventory or identification). Until 2013, the question was under which context did DNA collection of arrestees reside?

In Maryland v. King the Supreme Court indicated that DNA testing of felony arrestees resided in in the special needs context.[20] This means that the subjective intent of law enforcement should matter. Yet, the majority held that the DNA collection was for identification and that identification was the subjective intent of law enforcement.[21] Thus, the practice was held Constitutional under the 4th amendment.[22]

Personally, it’s hard to imagine that the actual subjective intent of law enforcement for collecting DNA is to identify the arrestee. As the dissent in King points out, the average response time for identification based on fingerprints is about 27 minutes.[23] However, DNA samples can take months to come back with identification.[24] Further, the fingerprint database includes “detailed identification information, including ‘criminal histories; mug shots; scars and tattoo photos; [and] physical characteristics like height, weight, and hair and eye color.’”[25] CODIS contains none of this, not even a name.[26] The only identification happening with CODIS is the matching of an already known individual to an unknown sample of DNA.

The dissent in King argued that the DNA was being used under an investigatory purpose, therefore the government should need probable cause before collecting the DNA.[27] However, probable cause for cold cases will rarely exist as the police did not have the probable cause needed to arrest the person for the initial crime in the first place.

Despite these arguments, DNA collection of an arrestee has been deemed Constitutional under the 4th amendment.


There is no dispute that DNA collection of arrestees aids in the accuracy of the criminal justice system. The results can exclude innocent persons and solve past and future crimes.[28] While the states and federal government hail the buccal swab as minimally invasive, it may be argued that the information of which it is capable of obtaining makes it signicantly invasive, not the procedure itself.

I hold serious doubts as to whether DNA collection from arrestees is a Constitutional practice under the 4th amendment. I agree with the dissent in Maryland v. King. Under their reasoning, the police must at least have probable cause to swab for DNA. In the context of decades old cold cases, the police surely do not have the probable cause needed to search the arrestee for the cold case because if they had it, they would’ve already searched and arrested the arrestee. In that sense, law enforcement is taking a dragnet approach to investigating crime. That sort of approach is not supported by the particularity requirement of the 4th amendment.


[1] Julie Samuels et al., Collecting DNA From Arrestees: Implementation Lessons, 270 NIJ J. 18, 19 (2012) (citing Louisiana as the first state to authorize DNA collection from arrestees).

[2] See id.

[3] Nat’l Conf. of State Legis., DNA Arrestee Laws (2013) [hereinafter “DNA Arrestee Laws”].

[4] Samuels et al., supra note 1, at 21.

[5] DNA Arrestee Laws, supra note 3.

[6] Id.; Samuel et al., supra note 1.

[7] DNA Arrestee Laws, supra note 3.

[8] See What Is a Buccal Swab?, Dynamic DNA Laboratories (Mar. 18, 2019),

[9] Id.

[10] Fed. Bureau of Prisons, Inmate DNA Sample Collection Procedures (2010) [hereinafter “Inmate DNA Sample Collection Procedures”].

[11] What is a Buccal Swab?, supra note 8.

[12] Rebecca Beitsch, DNA Upon Arrest: Solving Cold Cases or Presuming Guilt?, PEW (Jan. 12, 2017),; Frequently Asked Questions on CODIS and NDIS, FBI,

[13] Inmate DNA Sample Collection Procedures, supra note 10.

[14] Samuels et al., supra note 1, at 18 (noting the CODIS match that solved a rape case from a decade earlier); Maryland v. King, 549 U.S. 435 (2013) (solving a 6-year-old unsolved rape case); see also Michelle Taylor, Texas: Arrestee DNA Collection Solved Over 250 Cases in One Year, Forensic Mag (Nov. 20, 2020),

[15] Samuels et al., supra note 1, at 23.

[16] See id.

[17] Beitsch, supra note 12.

[18] Samuels et al., supra note 1, at 23.

[19] See Whren v. United States, 517 U.S. 806 (1996).

[20] King, 549 U.S. (2013).

[21] Id. at 465-66.

[22] Id.

[23] Id. at 478.

[24] Id.

[25] Id.

[26] Id.

[27] Id. at 466.

[28] See Inmate DNA Sample Collection Procedures, supra note 10.

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