DNA, crime and law enforcement
Personal Genetics Education Project (pgEd)
Harvard Medical School - Wu Laboratory
www.pged.org
Do Now:
Imagine that there have been a string of murders that appear to
be the work of one person. The police have a few leads, but
little conclusive evidence. They have DNA, which they believe
to be that of the murderer, but it does not match DNA profiles
in the criminal databases. The police don’t have enough
evidence to arrest the lead suspect, nor do they wish to alert
him of their interest in him. Instead, they obtain a warrant to
get a sample of DNA from a medical test of the suspect’s adult
daughter to compare with DNA from the crime scenes. She
does not know about this warrant and, therefore, has not
given her consent.
1. Should the police require permission to analyze a DNA sample
from the suspect’s child? Why or why not?
2. Take the position of one of the victim’s parents. Do you
support this tactic? Why or why not?
3. Take the position of the suspect’s daughter, who has had her
DNA secretly tested. Do you support this tactic? Why or why
not?
BTK Serial Killer – Dennis Rader
Source: El Dorado Police Department
What is a criminal DNA database?
• Database of DNA profiles that is maintained by
law enforcement agencies
• “Forensic Index” – Database of DNA profiles
collected at crime scenes
• “Offender Index” - Database of DNA profiles
collected from people who are arrested or
convicted of a crime
Big Idea: Compare DNA from the forensic and
offender indexes to find matches
Who is in U.S. criminal DNA databases?
• CODIS (the Combined DNA Index System):
The FBI’s program for linking the federal, state
and local DNA profiles in a single database.
• CODIS statistics (as of November, 2013):
- DNA profiles from over 10,692,400 people are
in the “offender index.”
- This includes DNA profiles from over 1,711,100
arrestees.
- DNA profiles from over 527,400 samples found
at crime scenes are in the “forensic index.”
www.fbi.gov/about-us/lab/biometric-analysis/codis/ndis-statistics
What types of crimes require a person to
provide a DNA sample?
• 49 out of 50 states collect DNA from convicted
felons.
• 33 states collect DNA from juvenile felony
offenders.
• 38 states collect DNA for sex crime misdemeanors,
while 12 also collect DNA for “other” misdemeanors.
“Other” misdemeanors can include:
Graffiti
Disorderly conduct (ex: protests)
http://en.wikipedia.org/wiki/File:RNC2008_day2_protest_by_matt_sandy.jpg
http://www.bbc.co.uk/london/content/imag
e_galleries/banksy_gallery.shtml?30
False
Advertising
http://healthinformatics.wikispaces.com/SketchersShapeUps
Supreme Court rules 5-4 that DNA can
be taken from arrestees
Photo: npr.org
Maryland v. King
What has changed since CODIS was
established in 1994?
• The databases are expanding. Some states are
broadening the criteria for entry into their offender
databases. For example, as of March 2012, New York
state includes all people convicted of a misdemeanor.
CODIS in 2002: 1.2 million offender profiles
CODIS in 2012: 9.7 million offender profiles
• Scientific leaps are creating new opportunities and
challenges.
• Familial searching has generated interest and
controversy.
What is familial searching?
• Familial searching targets specific family members
of people already in a DNA database.
• Law enforcement agencies collect DNA from a crime
scene and compare it to DNA profiles already in the
database. If a perfect match is not found, they may
look for a partial match with enough markers in
common to suggest a familial relationship.
• If a partial match is found, law enforcement
investigate family members further. They may need a
DNA sample from the family member to confirm the
connection. Sometimes, these samples are collected
in secret or from unexpected places, such as a cup,
cigarette or pizza crust from the trash.
What are the scientific controversies
related to crime and DNA?
Darryl Hunt reacts
after being cleared
of charges after
19 years in prison
for a murder he
didn’t commit
AP file photo
• Familial searching has helped law enforcement officials to make
breakthroughs in some cases, enabling them to catch notorious
criminals and exonerate innocent people.
• Critics say this puts an entire group of people – anyone who has a
biological relative with a DNA profile in an offender database – under
indefinite genetic surveillance.
• This technique disproportionately impacts minorities. For example,
African-Americans make up 13% of the U.S. population, but 40% of
the prison population.
http://quickfacts.census.gov/qfd/states/00000.html; http://www.ojp.usdoj.gov/bjs/pub/pdf/pjim06.pdf US Bureau of Justice Statistics
Discussion Questions
1. In the video clip, who was more persuasive – the Denver
district attorney or the attorney concerned about privacy
rights? Why?
2. Do you think familial searching is a tool more law
enforcement agencies should use? Why or why not? What
do you think about the idea that biological relatives of
people in genetic databases are under “genetic
surveillance?”
3. The reporter says, “Crime runs in families.” What does
she mean? Is this a reasonable conclusion? Why or why
not?