DNA Technology in Forensic Science - Innocence Project

Innocence Project Position on Familial Searching of DNA Databases

When DNA databases were first created and authorized in the United States, scientists, legal
practitioners (including the Innocence Project) and policymakers recognized the need to strictly
limit the government’s use of the intensely personal information contained in DNA databases out
of constitutional privacy concerns and the potential to further exacerbate existing racial
disparities in the criminal justice system.1 In fact, the Committee on DNA Technology in
Forensic Science, which was convened by the National Research Council to address issues in
forensic DNA testing, dedicated a full chapter in its 1992 report, DNA Technology in Forensic
Science (“NRCI”), to the social, economic and ethical concerns involved in the use of DNA
typing technology, noting:

Financial costs, potential harm to the interests of individuals, and threats to liberty
and privacy are only a few of the worries typically voiced when a new technology
is on the horizon. DNA typing technology has the potential for uncovering and
revealing a great deal of information that most people consider intensely private.2

When establishing the National DNA database, the federal government developed laws and
policies to respect those concerns: the original federal DNA database law authorized the
collection of DNA from only those convicted of a crime;3 the unauthorized disclosure of DNA
data from the National DNA database was made a criminal act, punishable by fine of up to
$100,000;4 and the national DNA database system (also referred to as CODIS) was prohibited
from including names or other personal identifiers of those whose DNA profiles it contained.5
States that enacted laws in order to participate in CODIS generally respected the same concerns.
For example, at its creation in 1994, the New York DNA database contained the profiles of only
those defendants convicted of a narrowly tailored list of felonies that included only certain
homicide, assault and sexual offenses.6

                                                           
1 See, e.g., E. Donald Shapiro & Michelle L. Weinberg, DNA Data Banking: The Dangerous Erosion of Privacy, 38
Clev. St. L. Rev. 455, 469 (1990) (citing A. 11073 (N.Y. 1990) (“DNA data banking potentially threatens one of the
most fundamental spheres of privacy in a democracy; A citizen's genetic make-up. Before embarking on the
expensive, complex and delicate task of creating a DNA data bank, it is essential that the forensic DNA technology
underlying the enterprise meet the highest standards of reliability and that the most rigorous privacy protection be
imposed.”).
2 Committee on DNA Technology in Forensic Science, National Research Council, DNA Technology in Forensic
Science 152 (National Academies Press 1992).
3 42 U.S.C. § 14132 (originally enacted as The Violent Crime Control and Law Enforcement Act of 1994, Title
XXI, § 210304, 108 Stat. 2069, which read: “[t]he Director of the Federal Bureau of Investigation may establish an
index of . . . DNA identification records of persons convicted of crimes . . .”).
4 42 U.S.C. § 14133(c).
5 See 42 U.S.C. § 14132; see also, FBI, Frequently Asked Questions (FAQs) on the CODIS Program and the
National DNA Index System, http://www.fbi.gov/about-us/lab/codis/codis-and-ndis-fact-sheet.
6 N.Y. Exec Law § 995-b (McKinney 1994) (“‘Designated offender’ means a person convicted of and sentenced for
any one or more of the following felonies as defined in the penal law: sections 120.05, 120.10, and 120.11, relating
to assault; sections 125.15 through 125.27 relating to homicide; sections 130.25, 130.30, 130.35, 130.40, 130.45,
130.50, 130.65, 130.67 and 130.70, relating to sex offenses; sections 205.10, 205.15, 205.17 and 205.19, relating to
escape and other offenses, where the offender has been convicted within the previous five years of one of the other
felonies specified in this subdivision; or section 255.25, relating to incest.”)

As reliance on DNA evidence grew, however, government practice began to implicitly and
explicitly disregard those considerations. As the NRCI states, “[i]nitial state efforts to develop
DNA profile databanks were . . . aimed at sex offenders. Interestingly, some states rapidly
expanded their programs to include all convicted offenders—without explicit weighing of the
potential benefits of possessing such persons’ patterns for solving crimes and the potential
costs.”7 Law enforcement crime labs created unauthorized and unregulated local DNA databases
to capture the DNA of many classes of innocent people, including crime victims, those who
provided DNA to aid law enforcement investigations, and others never convicted of a crime.8 A
number of state legislatures have expanded databases to officially include those not convicted of
crimes.9

The question of proper DNA database use has always been a balancing of public safety interests
versus privacy interests. The Innocence Project has always supported DNA databases of felony
offenders as a law enforcement tool; we saw that approach—as did virtually all others who
carefully considered the issue before their creation—as a proper balance of the two. Those
convicted of felonies are those most likely to commit the serious crimes for which DNA
evidence may be probative of guilt.10 Limiting the database to only felony offenders provides
law enforcement with a powerful tool for solving serious crimes, while still protecting the
privacy rights of everyone but those who have committed serious crimes.11

“Familial searching” of DNA databases exacerbates many existing concerns regarding DNA
database use, while also raising new ones. Familial searching is a practice where law
enforcement uploads the DNA profile recovered from crime scene evidence and compares it to
the DNA database not to find a match, but to look for near matches to people in the database.
Familial searches operate on the principle that crime scene DNA profile that closely match the
DNA of someone in the database may indicate that the perpetrator of the crime in question is a
family member of the person in the database12. As the expansion of databases has increased at

                                                           
7 Committee on DNA Technology in Forensic Science, supra n. 2, at 120.
8 See, e.g., Mark Hansen, DNA Dragnet: Critics Say Police Employed Heavy-Handed Tactics to Coerce More Than
1,200 People to Give Genetic Samples in the Search for a Serial Killer, ABA Journal, May 2004; Todd Cooper.
Chambers vows to act on his fury The Omaha lawmaker blames the mayor and police chief for a "reprehensible"
DNA sweep profiling black male OPPD workers, Omaha World Herald, June 29, 2004, at 1B.
9 At least 24 states and the federal government have laws that authorize arrestee DNA sampling. See, Nat’l Conf.
St. Legislatures, State Laws on DNA Data Banks,
http://www.ncsl.org/portals/1/Documents/cj/Table1DNAArresteeLaws.pdf.
10 See Committee on DNA Technology in Forensic Science, supra n. 2, at 118-120.
11 See Bureau of Justice Statistics, Department of Justice, Forensic DNA Analysis: Issues 25 (SEARCH Group, Inc.
1991) available at https://www.ncjrs.gov/pdffiles1/pr/128567.pdf (“it is not hyperbole to suggest that DNA
databanks could revolutionize efforts at [sic] apprehending violent and sex offenders.” (emphasis added)).
12 The same principal underpins what is called “fortuitous partial matching,” which is defined generally as the
inadvertent discovery that a forensic DNA profile is similar to an offender or arrestee profile. Fortuitous partial
matching can be the result of lower-stringency search parameters. In fact, the “CODIS system software was
designed to run moderate-stringency searches. This means that when a search is conducted against CODIS, the
computer compares a given DNA profile with the database, looking not only for perfect matches but also cases
where, for one or more loci, one sample contains only one allele . . . and the other is heterozygote . . . with one of the
alleles the same as the single one.” Sheldon Krimsky & Tania Simoncelli, Genetic Justice: DNA Data Banks,
Criminal Investigations, and Civil Liberties 68 (Columbia University Press 2010). Where analysts are knowingly
searching at a moderate-stringency setting, the argument that a partial match is fortuitous does not hold; the result is
foreseen. Familial searching and fortuitous partial matching are indeed two sides of the same coin, and any

an alarming rate, so too has the use of familial searching. Familial searching is uniformly being
performed without legislative authority13 and goes far beyond the original intent for database
searches. 14

It must be noted that familial searching has helped to solve a limited number of serious crimes15
—and that each one of these is terribly important. The question is whether the narrow
investigative benefit trumps the social costs incurred in the process. Investigations flowing from
familial searches are extremely labor intensive16 and, more often than not, do not result in
identification of the real perpetrator, suggesting that resources could be better spent on more
traditional forms of investigation.17

Becoming the police suspect in a serious crime is an intense burden that has very real financial,
emotional and liberty implications.18 Familial searching virtually guarantees that DNA
databases will create suspects out of innocent people, and because of the composition of DNA
databases, those innocent suspects will disproportionately be people of color. “[S]ocial groups
[that] both share genetic relationships and are over-represented in the database would experience

                                                                                                                                                                                               
distinction drawn between the two is “empty and dangerous,” and the concerns discussed herein apply equally to
both. Natalie Ram, Fortuity and Forensic Familial Identification, 63 Stan. L. Rev. 751, 755 (2011).
13 See Ram, supra n. 12, for a summary of the state of the laws and policies on deliberate (familial) and fortuitous
partial matching across the country. At the time of publication, four states, California, Colorado, Nebraska and
Texas, had adopted a statewide policy permitting familial searching. In all four instances, no authorizing legislation
supports the use of such searching. See also Erin Murphy, Relative Doubt: Familial Searches of DNA Databases,
109 Mich. L. Rev. 291, 302 (2010) (“[F]ormal law provides very little guidance.”).
14 DNA database “laws were enacted because of the high rate of repeat felonious behavior by convicted persons . . .
The laws are premised on the fact that criminals sometimes leave biological evidence at the crime scene and that the
comparison of the results of DNA typing of such samples with profiles stored in the forensic laboratory might lead
law-enforcement officials quickly to a prime suspect.” Committee on DNA Technology in Forensic Science, supra
n. 2, at 143.
15 See Frederick Bieber et al., Finding Criminals Through DNA of their Relatives, 312 Science 1315, 1315 (2006)
(“To date, searching DNA databases to identify close relatives of potential suspects has been used in only a small
number of cases, if sometimes to dramatic effect.”); see also Murphy, Murphy, supra n. 13, at 328 (“although there
have been numerous newspaper reports of isolated successes with familial searching, it seems plausible that the
sensational nature of such matches might mean that those stories are not the tip of the iceberg, but its entirety.”).
16 James M. Curran & John S. Buckleton, Effectiveness of Familial Searches, 84 Science & Just. 164 (2008)
(“familial searching is a high input exercise with investigators required to examine a large number of potential
leads.”).
17 See Murphy, supra n. 13, at 328-29. What is more, it has been suggested that the use of familial searching may in
fact harm police investigations because of a tendency to over-rely on the technique at the expense of these
traditional forms of investigation. Id. at 309-313.
18 Daniel J. Grimm, The Demographics of Genetic Surveillance: Familial DNA Testing and the Hispanic
Community, 107 Colum. L. Rev. 1164, 1184 (2007) (“like the African American community, the Hispanic
community is subject to embedded system multipliers that converge to amplify disproportionate risks of privacy
violations from DNA databanks”); see also Sonia Suter, All in the Family: Privacy and DNA Familial Searching, 23
Harv. J. L. & Tech. 309, 368-369 (2010) (“[T]he statistics concerning race and crime are deeply troubling. African
Americans, who make up 13% of the general population, represent, on average 40% of convicted felons, three times
greater than one would expect if race were not a factor in criminal convictions. Hispanics are also overrepresented
in prisons, although not to the same extent as African Americans. The probability that an African American,
Hispanic, and non-Hispanic white person will be incarcerated in his lifetime, respectively, is 18.6%, 10%, and 3.4%.
Not only are minority groups convicted at disproportionate rates, but there is also evidence that they are arrested
disproportionately and evidently with less basis than non-Hispanic Caucasians.”).

a disproportionate increase in genetic surveillance if familial searching were routinely
implemented.”19

Although the chance that two unrelated people match at thirteen or more sites
with every marker having at least one match (as will occur for parent-child pairs)
is small . . . , with genotypes from 2.75 million people in the CODIS Offender
Index, there should be many spurious matches at this level in the database. For an
average genotype, around 2,000 to 3,000 people in the Offender Index are likely
to have one or more matching alleles at all thirteen markers.20

Put differently, as CODIS expands, there is an ever-increasing likelihood that familial searching
will result in a number of false positives, that is, near matches to people who are not at all
related.

In the starkest of terms, innocent citizens may find themselves followed by police and their
discarded items the subject of unconsented-to DNA tests. Quite simply, familial searching
creates guilt by association.21

What is more, DNA databasing has frequently been justified on the ground that it uses only
“junk DNA,” or DNA that was “purposely selected because [it is] not associated with any known
physical or medical characteristics” and “do[es] not control or influence the expression of any
trait.”22 Familial searching, on the other hand, further intrudes into the privacy of people whose
DNA the government has in its possession by revealing more than solely the offender’s
identity.23 For these reasons and more, many remain convinced that such searching is a violation
of constitutional rights, including the rights to due process and to privacy.24 Solving serious
crimes is appropriately a top priority of our government; that does not mean, however, that
concerns about resource allocation, racial disparity and constitutional rights are without merit.

Based on the same concerns regarding DNA databases generally, the Innocence Project opposes
the practice of familial searching.

                                                           
19 Rori V. Rohlfs et al., Familial Identification: Population Structure and Relationship Distinguishability, 8(2) PLoS
Genet., 1-2 (2012).
20 Henry T. Greely, Daniel P. Riordan, et al., Family Ties: The Use of DNA Offender Databases to Catch Offenders’
Kin, 34 J.L.Med. & Ethics 248, 250 (2006).
21 See Murphy, supra n. 13, at 304 (“[F]amilial searches should be forbidden because they embody the very
presumptions that our constitutional and evidentiary rules have long endeavored to counteract: guilt by association,
racial discrimination, propensity, and even biological determinism.”).
22 U.S. v. Weikert, 504 F.3d 1, 3-4 (1st Cir. 2007) (internal citations omitted).
23 Those who are in the database and are identified as part of a familial search may: 1) be contacted by detectives; 2)
not even have relatives who could have committed the crime; 3) have relatives who are completely innocent; and 4)
have relatives who are not themselves in the database, but who will be under suspicion nonetheless. See Michael
Chamberlain, deputy attorney general, DNA Legal Unit, California Department of Justice, Memorandum to Attorney
General Jerry Brown, California, 3, June 6, 2007. What is more, familial searching may intrude on fragile family
dynamics by leading to the discovery of unknown children or misattributed paternity. See Ram, supra n. 12, at794. 
24 See Murphy, supra n. 13, at 337 (“[T]he partial match search, and the inference drawn from the match itself,
invoke constitutional scrutiny because they intrude on the legitimate expectation of privacy held by the relative in
her half of the offender's genetic code, and are impermissible because they do so without individualized or
particularized suspicion.”).

Nevertheless, should a state choose to adopt a familial searching policy, we believe the policy
must flow from authority granted by legislatures. The need for legislative authority was clearly
recognized upon the creation of DNA databases, and any extensions of power regarding their use
must also be made through legislation. Legislatures are uniquely capable of considering and
reflecting various concerns when making such decisions, including how the negative collateral
effects of the use of this tool can be minimized. Additionally, legislative action fosters public
debate in a manner far more robust than executive action or simple deference to law enforcement
decision-making.

To minimize the negative collateral effects of this practice, legislatures must require that familial
searches only be conducted following judicial supervision and approval. Judges faced with such
requests must consider whether:
‐ The crime is murder or a felony sexual assault;
‐ All other investigative leads have been exhausted;
‐ A DNA match would provide significant evidence of guilt;25
‐ The law enforcement agency has made a showing that the least intrusive means will be

used;26
‐ Police have an established deadline for analyzing DNA samples provided by individuals

identified in the familial search and must seek extensions, which should be granted for good
cause only; police should be required to report back to the court on the results of the search
and investigation;
‐ The officers investigating the leads generated by the familial search have been trained in
methods to enable them to not disclose familial connections, and agree not to do so; and
‐ Law enforcement will destroy the biological material and DNA profile of all
those investigated as a result of the familial search but not prosecuted within a stated time
frame.

In addition to this legal requirement, legislatures should require that:
‐ A committee, composed of a legal ethicist, genetic ethicist, law enforcement official, defense

lawyer, prosecutor, statistician, victim of a serious crime, and an innocent subject of a
familial search (or wrongfully convicted person, where the former does not exist in the state)
be established to provide advice to all judges in the state who receive a request for familial
search and to oversee the consideration of the data collected along with any familial
searches;
‐ Data related to familial searching be collected, which includes but is not limited to:

o the number of requests for familial searches (and the documentation related thereto);
o the number of times granted;
o the basis of each grant or denial;
o the number of individuals identified through a familial search;
o the methods used to narrow the pool of suspects and resulting pool size;
o the methods used to investigate leads;

                                                           
25 Typically, this will require that the crime scene DNA profile must be a single-source profile.
26 Typically, this will require that Y-STR, Mitochondrial, or other limiting DNA testing methods will be used to
narrow the initial pool of potential suspects generated by the familial search, so as to minimize intrusion on people
whose family members have no connection to the crime scene evidence.

o the costs of those investigations;
o the number of potential suspects identified;
o the race of those identified as suspects in the culled suspect pool;
o the personal impressions of the investigators involved in the post-familial search

investigation;
o the personal impressions and specific costs borne by those innocents investigated as a

result of the familial search; and
o whether the search ultimately resulted in a conviction of a person identified through

the familial search.
‐ All DNA databases and databanks that do not exist pursuant to explicit state legislative

authority, for example, victim and elimination sample databases, be dismantled and
destroyed.