For the Defense - Vol. 7, Issue 3 - 8

a DNA profile from a complainant's vulval swabs
were matched back to him, even though he lived six
hours away and cell phone records indicated that he
could not have made the round trip that quickly.12
Mr. Adam Scott was incarcerated for five months,
while authorities investigated. A technician at LGC
Forensics had accidentally reused a disposable plastic
tray because it was not marked it as having been
used a first time. Consequently, the vulval swab
sample from the rape case (which had no DNA in it)
was added to the same well as the sample from the
first case (described only as a " spitting incident " ).
In 2012, Silicon Valley multimillionaire Raveesh
Kumra was murdered in his home. DNA analysis
of the decedent's fingernails yielded a profile that
led to a database hit on homeless alcoholic Lukis
Anderson. The defense had noted that, at the time
of the murder, Mr. Anderson was already at the same
hospital that the decedent had been transported to
for three hours, with a blood alcohol level equal to
21 beers. Investigators for both the prosecution and
the defense discovered that the same ambulance
unit had transported both. It is believed that the
finger pulse oximeter was contaminated with Mr.
Anderson's DNA, which was then transplanted to the
fingernail of the victim.
CASE 3: GARMENTS AND BEDDING
Evidence: The defendant's DNA is detected on the
crotch of a pair of the complainant's underwear.
* CASE 3A:
The complainant and defendant are
lovers.
Except in rare circumstances, DNA analysis cannot
tell when the DNA was deposited. In this scenario,
the complainant and defendant have an intimate
relationship. Consequently, it should be expected
that each individual will have the other's DNA
on their clothing. Therefore, the DNA evidence is
moot as there is no way to determine the time or
circumstances under which the DNA was deposited.
*CASE 3B: The complainant and defendant are
former lovers.
When semen lands on natural fibers, the
spermatozoa can become entangled in those fibers.
Studies have shown that even repeated washings do
not remove all the sperm cells.13-15
a water-soluble component of seminal fluid, can
provide some insight as to laundering or not.
* CASE 3C: The complainant and the defendant live
together.
Given that the individuals share a living
environment, then it should be expected that the
defendant's DNA is present on multiple surfaces in
the residence. A substrate control (a sample from a
nearby but unstained area to test for background
DNA) could help determine layered DNA versus
comingled DNA.
* CASE 3D: The complainant and the defendant live
together, and biological children are also living in
the residence.
Given that children will inherit half of their DNA
from their mother and half from their father, there is
inherent genetic overlap between these individuals.
In fact, if a mother and father's DNA were mixed in
a sample, then any biological children of the parents
would appear as invisible in the mixture. This is
because all the possible alleles that the children
can inherit are already represented by the parents.
(e.g., if the parents have alleles AB and CD, then A,
B, C, and D will be detected, and the children, who
are AC and AD, will be " masked " by the parents).
Conversely, it is possible to have a mixture of the
children where the parents might seem invisible. This
is less likely across multiple loci, as the children may
not be fully representative of all the parental alleles
(e.g., if the children have alleles AC and AD; then A,
C, and D will be detected, so parent CD is " masked "
by the children, while parent AB is absent due to
the missing B). Due to this possible masking effect,
the children living in the household should also be
tested. Given these scenarios, substrate controls from
the garment should be tested to determine whether
the background DNA is coming from the complainant
or other household members.
These cells still
contain DNA that can be detected in testing. Again,
the DNA evidence is moot as there is no way to
determine whether the DNA was deposited during
a consensual or a non-consensual encounter. P30,
8 For The Defense l Vol. 7, Issue 3
For the Defense - Vol. 7, Issue 3

Table of Contents for the Digital Edition of For the Defense - Vol. 7, Issue 3
