Transcript Luminol and Blue Star - OldForensics 2012-2013

Luminol and Blue Star
Odalis Arellano,
Ashanty Barrios,
Ken Lin, and
Giovanni Delgado.
What Are They?
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Blue Star and Luminol are chemicals used to
detect trace amounts of blood left at a crime
scene.
They were designed to pick up the smallest
amount of blood.
The tests can still detect blood even when it
has been tampered with.
Luminol
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In the Luminol test, bloodstains are made visible in
total darkness by a blue light
Luminol powder is mixed with hydrogen
peroxide and hydroxide
The iron found on hemoglobin in the blood is the
catalyst in the oxidation reaction with the Luminol
solution.
This excites the electrons causing the blue glow that
only lasts about 30 seconds.
Luminol
Blue Star
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Blue Star is similar to Luminol
It does not alter the DNA of the blood it is testing. It
allows genotyping.
With Blue Star, small traces at about 1:10,000
dilutions can be detected, even if they were washed
with detergent.
Pictures can still be taken without the need of total
darkness unlike Luminol.
It is a newer test that is found in pill form.
Blue Star
Strengths and Weaknesses of Luminol
•Luminol chemiluminescence can be triggered by chemicals like copper or coppercontaining chemical compounds, and even some types of bleach, this means
that if an area was thoroughly cleaned with bleach and was then tested with
Luminol, you would obtain the blue glow.
• Luminol can also detect small amounts of blood in urine
• Luminol won’t work properly if the blood it’s tested on is animal blood.
• Luminol can react with animal droppings (aka animal poop) causing the same
glow as if it were blood.
• Luminol's presence can prevent other tests from being performed on a specific
test area. Experts have been able to extract some DNA however, from samples
tested with Luminol.
•The glow lasts only about 30 seconds.
Strengths and Weaknesses of Blue
Star
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Blue Star is one of the more sensitive tests for blood stains and can
detect smaller amounts of blood.
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Any blood stains appear immediately because they react with the Blue
Star.
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It doesn’t matter how much blood is present, in order for Blue Star to
work, the blood just has to BE there.
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Blue Star produces a much more intense and longer-lasting blue light
that does not need total darkness to be visible.
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This chemical has actually been used on crime scenes even though
it’s relatively new.
Major Cases Using These Chemicals
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In a cold case from 1992, Blue Star was used to find the location of a
man named Richard Woods. They found his body inside of his car but
officials didn’t believe that he was murdered there. Since he owned a
furniture store, they tested it and found “astounding” results in the
store’s office.
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Steve Mccausland and investigators found blood that belonged to 21
month old Ayla, in a house where they were reported to be missing.
The investigators used Luminol and found the blue glow in the families
basement. Since they only had one chance to test that area (the
reaction could not be replicated on area’s already tested) and they did
not have much evidence to prove the girl was abducted or murdered,
the case went cold. Officials have yet to find any more evidence that
could lead to the uncovering of her murder.
Several Brief Cases
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A man claimed that he did not hear his friend get
murdered during a sleep over. Police sprayed his
arms and they turned blue. They spayed the sink as
well and it also turned blue.
A pedestrian was shot and run over by a driver in a
white car. The driver was later caught and Blue Star
was used to test the car for blood. The driver was
then arrested after the blood and the DNA found on
the car matched the victim.
Review Questions
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What are some of the drawbacks of Luminol?
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What is Luminol and Blue Star used for?
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What are the main differences between Luminol and Blue Star?
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How long does the glow last and what color is it?
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Why is Blue Star considered better than Luminol by some?
Bibliography
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http://www.csigizmos.com/products/blooddetection/bluestar.html
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http://chemistry.about.com/od/glowinthedarkprojects/a/luminolbl
ood.htm
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https://www.ncjrs.gov/App/Publications/abstract.aspx?ID=23726
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http://www.bluestar-forensic.com/gb/bluestar-sensitivity.php
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http://www.bluestar-forensic.com/gb/bluestar-dna.php