Bender 2013
Through the Sands of Time Evidence from the
Earth
The Evidence:
Nine year old, Rebecca “Beck” O’Connell lived with her parents in Sioux Falls,
South Dakota. Her parents last saw Becky on the evening of May 8, 1990, when she left
home to buy candy at a nearby convenience store. Later that night, Becky’s mother and
stepfather reported her missing to the police. The following morning two men found
Becky’s remains in a wooded area along a river in Lincoln County South Dakota. An
autopsy suggested she had been beaten and sustained knife wounds on several parts of
her body. It was determined that she died as a result of a knife wound to her throat. A
man named Donald had been seen near her that evening and this was reported to the
police.
Investigators examined Donald’s truck and determined that Donald’s truck had
collected sand under the fenders. They also collected sand samples from the river bank
where the body was discovered. Both samples had unique characteristics and the
presence of a blue crystalline structure called Gahnite. The presence of these blue
crystals was believed to tie the suspect to the scene of the crime. Donald was convicted
of the murder of young Becky and sentenced to death. Donald’s conviction was
reversed by the South Dakota Supreme Court and Donald was re-tried and again
sentenced to death. His appeals continue. The strength of the physical evidence was in
large part the reason for the second conviction of Donald.
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Questions: There are potential problems associated with this type of analysis.
1. Explain why this type of evidence should only be used in conjunction with other
evidence.
2. Why is a comparison of similarity insufficient for a conviction?
3. Is the presence of specific special minerals in a sample enough to positively link a
person of interest to the scene of a crime?
The science of Forensic Geology is based in large part on the principle first stated
by Edmund Locard, “every contact leaves a trace.” Any time two objects touch a transfer
takes place. So whatever people touch and what touches them leaves a trace. If you are
able to find that transfer, that trace, you can determine where a person has been and
possibly what crime he or she has committed. The geologist will compare samples. The
questioned samples are associated with the crime. This is usually the material that has
been transferred. The other samples are the known samples that have come from
various identified locations that may be associated with the suspect or the suspects
alibi.
Geologists ask; are the samples similar? Could they have come from the same
source? If the soil on the victim’s body is different from the soil where the body was
discovered, what is the significance of the evidence? When the geologist compares the
samples he or she can say that the samples are similar, but physical evidence, as in the
case of soil, can never be IDENTICAL. There is always the possibility that a similar
material exists somewhere else on the Earth.
Beyond identification, forensic geologists can also look at the origin of particular
material. Here the examiner needs a broad knowledge of the geology and the best
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geologic and soil maps to answer questions. For example, if the soil on a body does not
match the location where the body is found, from where was the body moved?
Similarly, examiners can compare two samples, one associated with the suspect and the
other collected from the crime scene, to see if they had a common source: Does the soil
on the suspect's shoe compare with the soil type collected at the crime scene? Today it
will be up to you to determine if the evidence provided matches the elements of the
crime
Case 1
The complainant in a civil action alleged that a contractor had dumped asphaltcontaminated soil from a highway project onto his private property. Six specimens of
soil from various locations were received from the environmental laboratory
investigating the case. The laboratory manager requested that all six specimens be
examined to determine which one of the soil samples did not originate from the same
location as the other five. It was also requested that the examination be carried out
without the examiner knowing the origin of any of the soil specimens.
Data Table:
Sample Number
Texture
Shape(s)
Color
Match
1
2
3
4
5
6
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Questions:
1. Do any of the samples match each other?
2. Which of the samples match? How did you determine the match? Is your
conclusion enough to obtain a conviction?
3. Explain the significance of the evidence. What conclusions can be drawn as a
result of your findings?
4. Explain what should happen to the contractor, if anything?
Case 2
In the early spring, the body of a young adult female was seen floating down the East
River near midtown Manhattan. Several joggers had witnessed the body bobbing up and
down while they were running along the boardwalk that parallels the East River. The
dead woman, later identified as a missing woman by a sworn officer, and was pulled
from the river’s currents at the lower end of the east side of Manhattan.
At autopsy it was determined that the victim had been shot with a handgun. During the
investigation, it was discovered that the dead woman was in the process of attaining a
divorce from her estranged husband. Consequently, the husband became the prime
suspect of the investigation. A search warrant was issued for his upstate residence.
While executing the warrant, the crime scene officers discovered a water-stained men’s
right shoe in the suspect’s bedroom closet. Upon turning the shoe over a small quantity
of sand was detected adhering to the inside portion of its heel. The shoe was sent to the
laboratory for examination.
Before removal of the sand from the shoe’s heel, its presence was documented. The
shoe was then examined with a stereomicroscope. The questioned grains of sand
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seemed to adhere to the shoe’s heel as well as to each other. A total of 10 mg of sand
was removed from the shoe. After color analysis of the questioned sand, both the
stained area of the shoe, and the questioned sand specimen (QS1) were examined
chemically for the presence of sodium and chloride ions. Both tested positive for each
ion. Residue removed from the stained area of the shoe was further examined. Samples
of the river’s water were taken and allowed to evaporate. The known salty residue was
examined in the same manner as the questioned residue. Both the questioned and
known specimens were found to have the same trace elemental composition.
During the investigation, it was hypothesized that the suspect had taken his estranged
wife down to a local beach where upon he pulled her into the water and shot her, with
her own revolver. The revolver was never recovered. Known sand samples (KS1) from
the local beach were collected by one of the authors and compared to the QS1
specimen. After learning of the prosecution’s theory, the suspect stated to the
investigators that he believed the crime scene officers had placed his shoe into a saltwater fish tank he used to maintain in his residence, but had recently dismantled.
Known sand specimens were collected from various locations along the East River.
Testimony concerning the sand specimens was used at trial to help the jury reconstruct
the event.
Table Two:
Sand Sample
Texture
Shape
Color
Match
Shoe (QS1)
Beach (KS1)
Beach (KS2)
Beach (KS3)
Beach (KS4)
Aquarium (KS5)
Sand from the Body
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Questions:
1. Do any of the samples match each other? What is the significance, (why is it
important) that some of the samples match each other? What does this mean?
2. Which of the samples match? How did you determine a match? Is your
conclusion enough to secure a conviction of a person of interest?
3. Explain the significance of the evidence? What conclusions can be drawn as a
result of your findings?
4. What should happen to the husband? Are your opinions based on evidence?
Case 3
A young woman was found on a beach lying supine in the sand. She was killed by a blunt
force trauma to the head. Her van was on the beach next to her. Three days after the
victim’s body was found a suspect, who lived close to the beach, was arrested. The
crime scene unit searched his residence. Known sand samples from the beach, along
with sand samples from inside the victim’s van QS2 and QS4 were forwarded to the
laboratory. Questioned sand samples from the suspect’s clothing, sneakers QS1 and
QS5, socks QS6, and pants legs QS3 were collected by crime scene investigators, and
forwarded for comparison with the known beach sand, and the questioned specimens
from inside the victim’s van.Every sand sample was processed and fractions were used
for analysis.
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Table Three
Sand Sample
Texture
Shape
Color
Match
Sneakers (QS1)
Sneakers (QS5)
Beach (KS1)
Beach (KS2)
Van (QS2)
Van (QS4)
Socks (QS6)
Legs (QS3)
Questions:
1. Do any of the samples match each other? What is the significance, (why is it
important) that some of the samples match each other? What does this mean?
2. Which of the samples match? How did you determine a match? Is your
conclusion enough to secure a conviction of a person of interest?
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3. Explain the significance of the evidence? What conclusions can be drawn as a
result of your findings?
4. What should happen to the suspect? Are your opinions based on evidence?
Case 4
A female who had been running on a roadway in Central Park (CP) was found close to
death in an isolated area. She had been struck in the head with a large rock and dragged
several hundred feet into a ravine where she was further brutalized. After the attack, it
is believed she managed to travel a short distance and then collapsed from her injuries.
She lay bleeding until the morning, when she was discovered by some passers- by.
In a short time, numerous suspects were apprehended and held for questioning. After
questioning some were arrested. Their clothing was seized as evidence and packaged by
the crime scene unit. The clothing was taken to the laboratory for analysis. Questioned
aggregate soil specimens S3, S4, and S5 were removed from the suspect’s clothing. Two
aggregate soil specimens S2 and S2A were removed from the victim’s clothing, which
was sent to the laboratory by the investigating officer. Several known soil specimens S1
and S7 were collected at the crime scene.
The consistencies documented on the soil data sheet associate the questioned
specimens S3, S4, and S5 to the known other sources. Three of the suspects identified
by the victim were accused as the perpetrators of the crime can you establish a pattern
of evidence to support her unreliable eyewitness testimony?
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Sand Sample
Texture
Shape
Color
Match
Suspect S3
Suspect S4
Suspect S5
Victim S2
Victim S2A
Crime Scene S1
Crime Scene S7
Questions:
1. Do any of the samples match each other? What is the significance, (why is it
important) that some of the samples match each other? What does this mean?
2. Which of the samples match? How did you determine a match? Is your
conclusion enough to secure a conviction of a person of interest?
3. Explain the significance of the evidence? What conclusions can be drawn as a
result of your findings?
4. What should happen to the suspects? Are your opinions based on evidence?
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