How could investigators
prove a crime if it was
committed by an identical
twin?
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Biology of Twins
DNA of twins
That was what investigators in Jefferson County, Colo. faced in the
summer of 2003 when a young mother disappeared and was later found
murdered. Police believed she was killed by her husband with help from
his identical twin, but couldn't find enough evidence to prove it.
Anh Tong (left) and Duc Tong (right) were arrested after a fatal stabbing
took place on Jan. 26. Duc Tong was originally charged with the murder,
but this charge was later dropped and shifted to his twin brother Anh.
The judge found probable cause to hold both 19-year-olds in jail without
bond, despite a defense attorney argument that Manuel was not placed at
the scene by a witness
In 1999 in Grand Rapids, Michigan, when a female student was hit over
the head and raped.
Five years later, police matched DNA from the attack to Jerome Cooper but he has an identical twin, Tyrone. Both brothers already had records for
sexual assault
Identical Twins Charged With Rape! Mohammed and Aftab Asghar, 22,
were both arrested after DNA evidence was found at the scene which
provided a possible link to one, or both, the brothers. DNA Couldn't
Prove Who Committed the Crime.
The police in Marseille France are struggling to solve a sexual assault case.
They have solid video evidence and have even matched DNA from the
crime scene with two suspects but they still can’t figure it out. See, the
problem is that the suspects are identical twins.
In 2009, jewelry with a retail value of six million euros ($8.2m) was stolen
from Berlin's KaDeWe department store.
Traces of DNA were found in a glove found at the crime scene, and once
again the DNA led police to twin brothers, who walked free.
If we can’t use DNA, what can we
use?
Do identical twins have identical
fingerprints?
The basic answer is NO.
Forensic Science
Adapted from PPT by T. Trimpe 2007 http://sciencespot.net/
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While a fetus is forming, the pads on the fingers and palms
start to develop between weeks six to 13. The fingerprints are
complete by the time he is six months along.
How
Fingerprints
Form
•
•
Basal layer grows faster
than the epidermis on the
outside and the inner
dermis.
The basal layer buckles and
folds in several directions,
forcing complex shapes.
Fingerprint Principles
According to criminal investigators, fingerprints follow 3
fundamental principles:
S A fingerprint is an individual characteristic; no two
people have been found with the exact same fingerprint
pattern.
S A fingerprint pattern will remain unchanged for the life
of an individual; however, the print itself may change due
to permanent scars and skin diseases.
S Fingerprints have general characteristic ridge patterns
that allow them to be systematically identified.
History of Fingerprints
First Fingerprint Trial
S Directions: Read the article. Summarize in 3 to 4
sentences.
Classifying Fingerprints