How was forensic science used in these cases?
The Azaria Chamberlain Case
"some of the bloodstained items were removed from the tent" DNA samples could probably been used from the blood, or the blood could have been used to find out the babys blood type, which would help in the search.
The Shirley McKie Story
"her fingerprints were later supposedly found." Because of this small piece of evidence, it means that she could have been there, because everyone's fingerprint is different!
Jon Benet Ramsey
"the note was written from pen and paper found in Patsy's own writing corner." Chromatography would have been used to separate the ink on the note and in suspected, er, pens. Then the pattern that matched the note would probably have been used to write the note.
"an open basement window, an unidentifed boot print outside the house, a hand made strangling device and a possible sexual attack on the child." All of these things (even the body or the clothes) could have been tested for fingerprints, DNA or blood samples for testing.
Tuesday, November 18, 2008
Case Studys Part 1: The Case Study examples
Here are some examples of case studys that involve forensic science.
The Azaria Chamberlain Case
On the 17th August 1980, the Chamberlain family was camping at Uluru in Australia's Northern Territory, when at around eight o'clock at night, they heard a cry from the tent where their ten week old baby girl and four year old son were sleeping. Rushing to the tent, the mother of the child, Lindy saw a dingo near the tent's entrance and upon entering, realised with horror that her baby daughter Azaria, was missing and all that remained was a pool of blood on the floor. The police arrived and a search was organized but no traces of the baby were found.
The Chamberlains were interviewed the next morning and only some of the bloodstained items were removed from the tent, with many being left behind. The family was interviewed again later on that same day, by a different officer who thought the Chamberlains' recounts of the previous night were suspicious. A week passed and no new evidence was found, that is, until a tourist found Azaria's vest and jumpsuit. But despite this new piece of evidence, the crime scene was not sealed off and a full examination of the clothing was never conducted. This lack of proper crime scene and evidence analysis led the police to believe that Lindy Chamberlain was lying about her story. The lack of dingo bite marks and saliva on Azaria's jumpsuit and the fact that the baby's shoes were still tied inside the jumpsuit while the vest was inside out, heightened the police's suspicion even further. In 1981, it was however, concluded that Azaria was indeed taken by a dingo, allowing Lindy and Michael Chamberlain to at last get over the accusations after the tragic loss of their child and move on with everyday life.
This was however, not to be the case, because after a later analysis of the baby's clothing, it was found that there was a bloody handprint in the shape of a women's hand, reopening the case in 1982. Analysis of the Chamberlains' car also revealed a pair of scissors, baby's blood and some experts claimed that the rip marks on the baby's clothing were actually scissor stab marks. And so it was with this new evidence that another court case was held on the 2nd February, 1982. The case concluded for what was thought to be the last time, when Lindy was convicted with murder of her daughter and sentenced to life in prison. After serving six years in prison, there was a turn in the case when baby Azaria's jacket was unbelievably, found partly buried at Uluru. Just five days later, Lindy was immediately released from prison, but to this day, nobody knows the exact truth and we'll probably never know.
Jon Benet Ramsey
On the morning of the 27th December 1996, Patsy Ramsey called the police to report her 5-year-old daughter, Jon Benet Ramsey, missing. The little girl had disappeared from her bedroom and a ransom note demanding one hundred and eighty thousand dollars (exactly the amount John Ramsay, her father, had received as a bonus at work just days before), had been left behind. It was only hours later, that Mr Ramsey found his daughter's strangled and battered body in the basement of their home in Boulder, Colorado. Immediately after the accidental discovery of Jon Benet's body, the parents fell under the suspicion of the police, because a lack evidence was found that an intruder had entered and killed the little girl. In fact, no proper search was conducted when the Ramseys first reported the case and friends were allowed to freely enter and leave the house.
The Ramseys hired an attorney, publicist and investigators to defend their case, when they and their son, Burke (9 at the time of Jon Benet's death), were interviewed by the police. In separate rooms, all three members of the Ramsey family were interviewed. After the interview, it was suspected that Patsy Ramsey wrote the ransom note herself, as the note was written from pen and paper found in Patsy's own writing corner. The evidence found in the basement however, bore all the classic signs of a murder by an intruder, including an open basement window, an unidentified boot print outside the house, a hand made strangling device and a possible sexual assault on the child.
At the time, police were confident that the case would be successfully solved using the DNA as evidence, but almost nine years later, the police have still not solved the case, no new leads have been found and none of the members of the Ramsey family have admitted to the murder. To this day, police are still attempting to find the person responsible for the murder of Jon Benet and the case remains unsolved.
The Shirley McKie Story
In February 1997, a British policewoman, Shirley McKie, was accused of perjury after testifying at a murder trial, stating that she hadn't been in the murder victim's house, where her fingerprints were later supposedly found. Shirley's house was searched and she was taken back to the police station where she herself was strip-searched and detained because of a controversial fingerprint that was found at the victim's house.
The Scottish Criminal Records Office, responsible for the detection of Shirley's thumbprint at the crime scene, had 4 experts who certified the authenticity of the fingerprints that they certified, definitely belonged to Shirley. However, Shirley persisted her innocence with the matter and was acquitted during her trial, saved from a potential 8 years imprisonment after two American fingerprinting experts endorsed that the fingerprint did not belong to Shirley. After much media activity, legal action and controversy, Michael Russell, a member of Scottish parliament, successfully requested different fingerprinting experts from around the world to verify the ownership of this fingerprint and have had to date, 171 certifications from 18 different countries that the fingerprint did not belong to Shirley.
The main concern with the entire issue was not only its affect on Shirley's career, but also because it concerns the accuracy of the Scottish Criminal Record Office's earlier assertions. A civil trial, expected to be 5 weeks long, is yet to be held on the 7th February 2006, almost ten years after the beginnings of the perjury case. The death of Marion Ross, the murder for which Shirley originally testified against, remains however, yet a mystery.
Sources: http://library.thinkquest.org/04oct/00206/text_casestudies.htm
The Azaria Chamberlain Case
On the 17th August 1980, the Chamberlain family was camping at Uluru in Australia's Northern Territory, when at around eight o'clock at night, they heard a cry from the tent where their ten week old baby girl and four year old son were sleeping. Rushing to the tent, the mother of the child, Lindy saw a dingo near the tent's entrance and upon entering, realised with horror that her baby daughter Azaria, was missing and all that remained was a pool of blood on the floor. The police arrived and a search was organized but no traces of the baby were found.
The Chamberlains were interviewed the next morning and only some of the bloodstained items were removed from the tent, with many being left behind. The family was interviewed again later on that same day, by a different officer who thought the Chamberlains' recounts of the previous night were suspicious. A week passed and no new evidence was found, that is, until a tourist found Azaria's vest and jumpsuit. But despite this new piece of evidence, the crime scene was not sealed off and a full examination of the clothing was never conducted. This lack of proper crime scene and evidence analysis led the police to believe that Lindy Chamberlain was lying about her story. The lack of dingo bite marks and saliva on Azaria's jumpsuit and the fact that the baby's shoes were still tied inside the jumpsuit while the vest was inside out, heightened the police's suspicion even further. In 1981, it was however, concluded that Azaria was indeed taken by a dingo, allowing Lindy and Michael Chamberlain to at last get over the accusations after the tragic loss of their child and move on with everyday life.
This was however, not to be the case, because after a later analysis of the baby's clothing, it was found that there was a bloody handprint in the shape of a women's hand, reopening the case in 1982. Analysis of the Chamberlains' car also revealed a pair of scissors, baby's blood and some experts claimed that the rip marks on the baby's clothing were actually scissor stab marks. And so it was with this new evidence that another court case was held on the 2nd February, 1982. The case concluded for what was thought to be the last time, when Lindy was convicted with murder of her daughter and sentenced to life in prison. After serving six years in prison, there was a turn in the case when baby Azaria's jacket was unbelievably, found partly buried at Uluru. Just five days later, Lindy was immediately released from prison, but to this day, nobody knows the exact truth and we'll probably never know.
Jon Benet Ramsey
On the morning of the 27th December 1996, Patsy Ramsey called the police to report her 5-year-old daughter, Jon Benet Ramsey, missing. The little girl had disappeared from her bedroom and a ransom note demanding one hundred and eighty thousand dollars (exactly the amount John Ramsay, her father, had received as a bonus at work just days before), had been left behind. It was only hours later, that Mr Ramsey found his daughter's strangled and battered body in the basement of their home in Boulder, Colorado. Immediately after the accidental discovery of Jon Benet's body, the parents fell under the suspicion of the police, because a lack evidence was found that an intruder had entered and killed the little girl. In fact, no proper search was conducted when the Ramseys first reported the case and friends were allowed to freely enter and leave the house.
The Ramseys hired an attorney, publicist and investigators to defend their case, when they and their son, Burke (9 at the time of Jon Benet's death), were interviewed by the police. In separate rooms, all three members of the Ramsey family were interviewed. After the interview, it was suspected that Patsy Ramsey wrote the ransom note herself, as the note was written from pen and paper found in Patsy's own writing corner. The evidence found in the basement however, bore all the classic signs of a murder by an intruder, including an open basement window, an unidentified boot print outside the house, a hand made strangling device and a possible sexual assault on the child.
At the time, police were confident that the case would be successfully solved using the DNA as evidence, but almost nine years later, the police have still not solved the case, no new leads have been found and none of the members of the Ramsey family have admitted to the murder. To this day, police are still attempting to find the person responsible for the murder of Jon Benet and the case remains unsolved.
The Shirley McKie Story
In February 1997, a British policewoman, Shirley McKie, was accused of perjury after testifying at a murder trial, stating that she hadn't been in the murder victim's house, where her fingerprints were later supposedly found. Shirley's house was searched and she was taken back to the police station where she herself was strip-searched and detained because of a controversial fingerprint that was found at the victim's house.
The Scottish Criminal Records Office, responsible for the detection of Shirley's thumbprint at the crime scene, had 4 experts who certified the authenticity of the fingerprints that they certified, definitely belonged to Shirley. However, Shirley persisted her innocence with the matter and was acquitted during her trial, saved from a potential 8 years imprisonment after two American fingerprinting experts endorsed that the fingerprint did not belong to Shirley. After much media activity, legal action and controversy, Michael Russell, a member of Scottish parliament, successfully requested different fingerprinting experts from around the world to verify the ownership of this fingerprint and have had to date, 171 certifications from 18 different countries that the fingerprint did not belong to Shirley.
The main concern with the entire issue was not only its affect on Shirley's career, but also because it concerns the accuracy of the Scottish Criminal Record Office's earlier assertions. A civil trial, expected to be 5 weeks long, is yet to be held on the 7th February 2006, almost ten years after the beginnings of the perjury case. The death of Marion Ross, the murder for which Shirley originally testified against, remains however, yet a mystery.
Sources: http://library.thinkquest.org/04oct/00206/text_casestudies.htm
Sunday, November 16, 2008
DNA fingerprinting
The DNA alphabet is made up of four building blocks – A, C, T and G, called base pairs, which are linked together in long chains to spell out the genetic words, or genes, which tell our cells what to do. The order in which these 4 DNA letters are used determines the meaning (function) of the words, or genes, that they spell.
In the example above, DNA collected at the scene of a crime is compared with DNA samples collected from 4 possible suspects. The DNA has been cut up into smaller pieces which are separated on a gel. The fragments from suspect 3 match those left at the scene of the crime, betraying the guilty party.
Finally, genetic fingerprinting can help us to predict our future health. DNA fingerprinting is often used to track down the genetic basis of inherited diseases. If a particular pattern turns up time and time again in different patients, scientists can narrow down which gene(s), or at least which stretch(es) of DNA, might be involved.
The chemical structure of everyone's DNA is the same. The only difference between people (or any animal) is the order of the base pairs. There are so many millions of base pairs in each person's DNA that every person has a different sequence.
Using these sequences, every person could be identified solely by the sequence of their base pairs. However, because there are so many millions of base pairs, the task would be very time-consuming. Instead, scientists are able to use a shorter method, because of repeating patterns in DNA.
These patterns do not, however, give an individual "fingerprint," but they are able to determine whether two DNA samples are from the same person, related people, or non-rela
ted people. Scientists use a small number of sequences of DNA that are known to vary among individuals a great deal, and analyze those to get a certain probability of a match.
ted people. Scientists use a small number of sequences of DNA that are known to vary among individuals a great deal, and analyze those to get a certain probability of a match. DNA fingerprinting is commonly used to probe our heredity. Since people inherit the arrangement of their base pairs from their parents, comparing the banding patterns of a child and the alleged parent generates a probability of relatedness; if the two patterns are similar enough (taking into account that only half the DNA is inherited from each parent), then they are probably family. However, DNA fingerprinting cannot discriminate between identical twins since their banding patterns are the same.
Perhaps the best known use of DNA fingerprinting is in forensic medicine. DNA samples gathered at a crime scene can be compared with the DNA of a suspect to show whether or not he or she was present. Databases of DNA fingerprints are only available from known offenders, so it isn't yet possible to fingerprint the DNA from a crime scene and then pull out names of probable matches from the general public.
In the example above, DNA collected at the scene of a crime is compared with DNA samples collected from 4 possible suspects. The DNA has been cut up into smaller pieces which are separated on a gel. The fragments from suspect 3 match those left at the scene of the crime, betraying the guilty party.
Finally, genetic fingerprinting can help us to predict our future health. DNA fingerprinting is often used to track down the genetic basis of inherited diseases. If a particular pattern turns up time and time again in different patients, scientists can narrow down which gene(s), or at least which stretch(es) of DNA, might be involved.
Microscopes
Microscope: an optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small to be seen or too small to be seen distinctly and in detail by the unaided eye.
How it works:
A microscope uses the same trick as a refracting telescope — light waves being bent as they travel through glass. In a telescope, the idea is to bend parallel light from very faraway objects into a small focus at the eye. In a microscope, the idea is to bend spreading-out light into a parallel path, then bend that light into a small focus at the eye.
First, we have to light up the object. A mirror mounted under the microscope stand does the job. Light bounces off the mirror, passes through and around our object(mounted f
irmly to a microscope slide), and into the objective lenses. These lenses bend some of the spread-out light beams from the object into straight line paths that travel through the microscope tube. Next, the light beams reach the eyepiece lenses. These lenses bend the light back into your eye, so you can see the object up close and personal.
The power of the microscope depends on how much each lens bends the light. Usually, the power is written right on the microscope itself. 40x, for instance, means that the image at the eyepiece is 40 times larger than real life.
Facts:
How it works:
A microscope uses the same trick as a refracting telescope — light waves being bent as they travel through glass. In a telescope, the idea is to bend parallel light from very faraway objects into a small focus at the eye. In a microscope, the idea is to bend spreading-out light into a parallel path, then bend that light into a small focus at the eye.
First, we have to light up the object. A mirror mounted under the microscope stand does the job. Light bounces off the mirror, passes through and around our object(mounted f
irmly to a microscope slide), and into the objective lenses. These lenses bend some of the spread-out light beams from the object into straight line paths that travel through the microscope tube. Next, the light beams reach the eyepiece lenses. These lenses bend the light back into your eye, so you can see the object up close and personal.The power of the microscope depends on how much each lens bends the light. Usually, the power is written right on the microscope itself. 40x, for instance, means that the image at the eyepiece is 40 times larger than real life.
Facts:
- Most microscopes use more than one lens for the objective and the eyepiece. This helps prevent a problem called “chromatic aberration”. While it’s true that light is bent as it passes through glass, it’s also true that some colours are bent more than others. The multiple lenses in the objective and the eyepiece help to correct that problem.
- Different types of microscopes have been used to look at human cells, identify minerals, solve crimes, see how freezing affects food, study metals, and find the causes of crop diseases.
Microscopes are an essential tool in medicine too. They have been used to identify the causes of many deadly diseases like malaria and tuberculosis. - Microscopes can also help to find out why a person or animal died.
- Scientists can even use a microscope to figure out where illegal drugs come from. For example, looking at opium crystals through a microscope reveals different shapes depending on where the poppies they came from were grown. This information can help pinpoint the source of illegal drugs.
Sources: http://www.yesmag.ca/how_work/microscope.html, How stuff works (image), http://www.dreamstime.com/ (image)
Wednesday, November 12, 2008
Chromatography
Chromatography is a method for analyzing complex mixtures (such as ink) by separating them into the chemicals from which they are made. Chromatography is used to separate and identify all sorts of substances in police work. Drugs from narcotics to aspirin can be identified in urine and blood samples, often with the aid of chromatography.
It works because some of the coloured substances dissolve in the liquid (like ink) better than others, so they travel further up the paper.
In all chromatography there is a "mobile phase" and a "stationary phase". The mobile phase moves through the stationary phase picking up the compounds to be tested. As the mobile phase continues to travel it takes compounds with it. At different points the different components are 
going to be absorbed and will stop moving. This is how the results of chromatography are gotten, from the point at which the different components of the compound stop moving and separate.
going to be absorbed and will stop moving. This is how the results of chromatography are gotten, from the point at which the different components of the compound stop moving and separate.Blood Types
We all have these little marker things called antigens on the surface of our red blood cells. These are so tiny they can't even be seen under a microscope. Everyone's got different ones, in fact, only identical twins will ever possess all the same antigens.
Blood groups, Part 1: The ABO system
The ABO system also contains lots of little antibodies in the plasma, antibodies being the body's natural defence against antigens. These are pretty much the opposite of other groups. So...
If it is present, the blood is positive, if not, it is negetive. For example, someone from Group A will have it, and will therefore be classed as A+ (or A positive). While the ones that don't, are A- (A negative). It's the same for groups B, O and AB.
This doubles the number of different blood types to be matched, because you shouldn't mix blood type A+ with blood type A-.
The Top Ten uses of blood are:
1. General surgery (23%)
Blood groups, Part 1: The ABO system
- If you have blood group A, you've got A antigens covering your red cells.
- Blood group B means you have B antigens.
- Group O has neither.
- Group AB hs a bit of both.
The ABO system also contains lots of little antibodies in the plasma, antibodies being the body's natural defence against antigens. These are pretty much the opposite of other groups. So...
- Group A has anti-B antigens
- Group B has anti-A
- Group O has both
- Group AB has none
Blood groups, Part 2: The RH system
It gets a bit more complicated when we bring in the RH antigen. Som people have it, some people don't.If it is present, the blood is positive, if not, it is negetive. For example, someone from Group A will have it, and will therefore be classed as A+ (or A positive). While the ones that don't, are A- (A negative). It's the same for groups B, O and AB.
This doubles the number of different blood types to be matched, because you shouldn't mix blood type A+ with blood type A-.
The Top Ten uses of blood are:
1. General surgery (23%)
2. General Medical (15%)
3. Cardiothoracic - heart and chest surgery (13%)
4. Orthopaedics - bones and bone diseases (11%)
5. Haematology - blood diseases (9%)
6. Accident and Emergency (8%)
7. Renal - kidneys - and Neonatel and Paediatrics - treatment of newborns and children (6%)
8. Intensive care (4%)
9. Obstetrics and Gynaecology - pregnancy and childbirth (3.5%)
Sources: http://www.blood.co.uk/, http://www.foothill.net/(image)
Tuesday, November 4, 2008
Fingerprints
There are three types of patterns associated with fingerprints. They are:
Each of the three pattern types have points which are used for classification. There are two different types of points, cores (the centre of a loop) and deltas (the area where there is a triangulation a dividing of the ridges).
In the loop pattern, there is 1 core and 1 delta. 
In the whorl pattern, there are two deltas.
There are no cores or deltas in the arch pattern
There are two types of impressions involved in taking fingerprints. The upper ten impressions are taken individually, thumb, index, middle, ring, and little fingers of each hand. These are referred to as the "rolled" impressions because the fingers are rolled from one side of the fingernail to the other.
The impressions at the bottom of the card are taken simutaneously without rolling, printing all of the fingers of each hand at a forty-five degree angle and then the thumbs. These are referred to as "plain," "slapped," or "flat" impressions. The plain impressions are used to verify the rolled impressions.
Sources: http://www.fbi.gov/hq/cjisd/takingfps.html
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