Simple Blood Pattern Analysis

In Chapter 18 it the prosecution discusses that they were given the clues to look for trace DNA evidence on Helena’s body by using blood stain analysis to determine where she was attacked. This lead them to discover areas on her body where an attacker might have left DNA such as the blood around her ankles and under her fingernails. After watching the video last week which included a segment about blood stain analysis I wanted to do a little more research on it. I learned that “Bloodstains are classified into three basic types: passive stains, transfer stains and projected or impact stains”. (Source Article) Usually most Blood Pattern Analysis happens after they have categorized the stain because certain stains are more common with certain crimes. Also often footprints and other markings can be identified and used as evidence which I thought was very neat. Overall the article has a lot of good information about blood pattern analysis and I recommend you check it out.

Source Article

Simple Blood Pattern Analysis

Matching Hairs and Blood Types

Two types of evidence found at the crime scene of Helena Greenwood’s assault were three strands of pubic hair, and a semen sample. Mona Ng, the criminologist who examined each piece of evidence, noted that:

“Two of the hairs could not be associated with the suspect Fredriani. The third hair could not be excluded as possibly coming from him.”  – Weinberg, p89

After checking the FBI website for information on forensic hair analysis, I learned that hair evidence can easily determine the race of a suspect and even the sex or age, albeit with more difficulty. Even though two of the strands found couldn’t be linked to Fredriani, the third could have belonged to a number of other men of the same race; Dr. Ng further explained that 14% of  population shares the blood type found in the semen sample, a statement which also expands the number of possible suspects when applied to the Bay Area alone. For these reasons I find it slightly illogical to convict Fredriani with what appears to be coincidental evidence.

https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/deedric1.htm/

Matching Hairs and Blood Types

Justice or Revenge

In this chapter the jury was not notified of Helena’s death. Obviously this happened while the trial was underway, not before. This makes me think what if the jury had known that she was murdered. Do you think the punishment toward the defendant would have been more harsh? or is it just a humane right for the jury to be notified of this death. I feel if the jury had known about this, this would have forced a biased opinion, maybe it is right but the punishment would have to fit the crime and the jury would have been thinking in vengeful ways because the last memory Helena had was one of hate due to the defendants actions.

Justice or Revenge

Science vs Police

“Eventually tracked down by a marriage between science and police work” -(Weinberg 125)

Science is often seen as revolutionary and and answer for all things. However in some aspects of society specifically religion it is seen as a rival or conflict. In the book “Pointing From The Grave” the author illustrates the importance of a successful and productive marriage between science and police work. In pop culture especially in CSI shows science and police always go hand in hand from finger print scanning to the autopsy to even blood stains on a carpet. However in reality it seems that with the increasing police force and need for more guns and ammunition, forensics and science almost seemed to be cast aside. There have been even politician trying to cut scientific research for the need of military and defense spending. However, as with the view of history there needs to be a strong relationship between science and police work. In the end science offers and answers all the important questions posed by the police force.

Science vs Police

Genetic Fingerprinting Solving Cases

I found Alec Jeffery’s discovery of genetic fingerprinting very interesting and of course it has been very useful in solving crimes since its birth.  At this point in the book, Paul has been convicted for the sexual act against Helena Greenwood, but the fact that 14% of the total population had the same matching secretion as the semen left behind on her pillowcase makes the case a little less certain.  Paul’s attorney desperately tried to argue, even though his client matched, that 14% of the people in the area is a large number of possible offenders.  If genetic fingerprinting were to be used, prosecutors could tell for certain if the semen left at the scene of the crime was in fact Paul’s.  The same way that Colin Pitchfork was convicted for his brutal double rape and homicides, Paul could definitely revealed as the culprit.  This type of DNA analysis could also be used to find Helena’s killer.  Below is a link to an article that highlights an interview that Alec Jeffery participated in.  Jeffery’s discovery all the way back in 1984 is discussed.     

Genetic Fingerprinting Solving Cases

The Body After Death

“When the first officers arrived, Roger was sitting beside Helena, crying, gently brushing flies from her eyes.” -Weinberg, pg 70

As morbid as it sounds, this quote reminded me of when we learned about the stages of decomposition of a human body, and different ways to tell how long a person had been dead. One of those methods involved maggots, as flies would lay eggs on corpses, and you could estimate how long a person had been dead by looking at which stage of life the maggots were in. However, in this case, it’s much easier to estimate how long Helena had been dead, as we know she was on the phone just before nine, and she was found in the early afternoon; besides, I don’t know if forensic entomology was well-known or well-used in 1985, so this technique might not have been available anyway.
But we also learned about the different stages the body goes through, and about how long it takes to get to each stage. I didn’t remember exactly what those stages were or how long each took, so I looked it up.
Immediately following death, the skin becomes “tight and grey in color,” the muscles relax, and the body’s temperature starts dropping (approximately 1.5 degrees Fahrenheit per hour, depending on environmental factors). We know that Helena wasn’t found immediately following her death. So onto the next stage.
After thirty minutes, “the skin gets purple and waxy” and lips, fingernails and toenails become pale as the blood is drained from them. The blood begins to pool in the lower parts of the body, depending on the position the body is in; those parts of the body become dark purple or blue, and is called lividity. We see this in the book, describing the change in color of Helena’s back and shoulders, except the parts where there was pressure. So Helena was dead for at least half an hour. Let’s look at the next stage.
By the time four hours have passed, rigor mortis sets in. Rigor mortis is when the muscles in the body stiffen, making it difficult or impossible to change the position of the body. It isn’t clear if Helena’s body has reached this stage yet; if not, then it’s likely she had been dead less than four hours when she was found.

Website used: http://www.anomalies-unlimited.com/Death/Stages.html

The Body After Death

Skin Cells and DNA

After reading chapter 6 from Pointing from the Grave, I was very alarmed by the events that occurred. It was very surprising to be in the midst of the trial and then to learn of Helena’s death. While this took me by surprise, I did like how the novel progressed in the field of biotechnology and forensics. In this chapter we were introduced to a new form of biotechnology and crime scene analysis through the way in which evidence was collected from the crime scene, how evidence was analyzed, and how that evidence will be used. Specifically, I thought it was interested that now we can understand DNA through skin cells gathered from underneath Helena’s fingernails. Skin cells shed every day and have many traces of DNA with in them. Yet again, we learned of a way in which DNA can be detected. The link below goes into detail about how analysts can extract the DNA from skin cells from a supernatant and a gathered pellet. The DNA can then be analyzed. I think it is very interesting that even the smallest traces of DNA play very large roles in detecting a suspect. It is also interesting to see how technology has advanced so much as seen in the explanations of the link below.

http://www.forensicmag.com/articles/2012/06/touch-dna-analysis-using-literature-help-answer-some-common-questions

Skin Cells and DNA

DNA In Hair Samples

One of the most controversial topics in Pointing From the Grave, so far, has been determining whether or not the fingerprint found on the teapot is enough to incriminate Frediani. Three samples were collected: the fingerprint on the teapot, the semen, and pubic hairs. Now that the fingerprint came out to a match and qualified Frediani to be a suspect, and the samples of semen were sent to a lab,  the only evidence that can be tested is the pubic hairs. However, Frediani’s attorney claims that the pubic hairs could belong to anyone including, Helena herself, her husband, or any guest that has ever slept in their bed. Through the DNA analyzing technology that we have developed we are able to analyze the DNA in hair strands. However, I did more research about the process of DNA testing using hair samples. To my surprise, hair samples do not actually provide the most accurate sample of DNA. In fact, the article claims that hair samples are the “most overestimated and misrepresented DNA samples”(Hughes).  I have attached the article below. Check it out it!

taken from the article whose link is provided below.
taken from the article whose link is provided below.

http://www.forensicmag.com/articles/2013/04/challenges-dna-testing-and-forensic-analysis-hair-samples

DNA In Hair Samples

Development of Forensics

In Chapter 4, I think it was really interesting how they talked about the development of finger printing and DNA testing in general.  Forensic science is an enormous part of everyday life in every country now, especially in law enforcement.  Before forensic science, “justice” was pretty much a huge blame game, with the defendant claiming one thing and the plaintiff claiming another.  Finger printing and DNA testing has eliminated the guessing game in the justice system, providing concrete evidence to back any claim made in court.  But, the development of this science did not happen over night.  Finger printing came first, the blood tests, and so on.  Scientists all over the world were working simultaneously to transform the science in to what it is today.  However, did any of these scientists work together or examine each other’s works?  Could they have split up the work and developed it more quickly, or was the gradual increase of technology and knowledge necessary in making forensic science what it is today?

Development of Forensics

Forensic Science

“The techniques employed to reveal–and identify–fingerprints have become increasingly sophisticated. Chemicals like ninhydrin can stain absorbed fingerprint sweat patterns on paper, making them visible, while superglue fumes can lift prints off human skin.” -Weinberg, pg 49

Reading this book makes me really glad that I took a course on forensic science in high school. Two of the main topics in this chapter, added in to help us understand the science behind Helena’s case, are subjects that we discussed in my forensics class: fingerprinting and blood typing. We learned about the different ways to reveal fingerprints, including the techniques that use ninhydrin and superglue. But when we spent a week practicing such techniques, we focused on the different kinds of fingerprinting powder–typical black powder, white or silver powder for dark surfaces, even magnetic powder for delicate surfaces that you don’t want to mar with a brush in order to remove the excess powder.
We also learned about blood typing, and practiced using anti-serums on synthetic blood to figure out which blood type we were working with. Something else we learned regarding blood types that wasn’t mentioned in the book is the Rh factor. In addition to being type A, B, AB, or O, your blood type can also be positive or negative. This refers to whether or not your blood contains a particular protein, and is also necessary information to have in order to have safe blood transfusions. Blood types that contain the protein can safely mix with blood that has the protein or doesn’t have the protein; negative blood types can only mix with other negative blood types.
I’m finding this book particularly interesting because I already possess so much background knowledge that’s helping me understand all the scientific techniques being discussed.

Forensic Science

PGM Testing

Chapter 5 of Pointing from the Grave, rerouted back to the trail of Frediani and Helena. Throughout this chapter, results of the semen tests were shared. It was stated that the analyst was able to deduce that Frediani is an O secretor; however, it wasn’t with great confidence that this evidence was accurate. As a result Chaput asks the analyst to

“do any further testing of any other enzymes and she said she would attempt to do that” -Weinberg, p58.

I thought this was very interesting because I thought that when a test was done, all of the enzymes would be extracted. In addition, I was wondering what Chaput meant by enzymes being tested or how a PGM test was done. After doing research on PGM testing (seen in the link below), I found out that they conduct this experiment by testing the enzymes found in the red cell membrane. These are PGM’s or genetic markers are protein enzymes that are found throughout the body. In the discovery these PGM’s, there were also three phenotypes which correlated to two alleles allowing for a more highly specific genetic marker in crime scene investigations. Overall, I thought it was very interesting to see and learn of another form of forensic biotechnology used through the help of DNA. DNA really is the platform for new techniques to arise.

http://www.practicalhomicide.com/Research/LOjun2010.htm

PGM Testing

Forensics Today

“The only evidence that linked him to the case was a single fingerprint, but that could be enough. In the courtrooms of the world, fingerprints and blood and semen stains were increasingly playing the dominant role. Forensic science was leaping from the test tube to tap criminals on their shoulders like a triumphant child  in a life or death game of grandmother’s footsteps.

Forensic science plays a huge role in crime cases these days. With the expansion of technology, I am curious as to how forensic science has changed and grown. Do forensic scientists look at camera and video evidence more so than physical evidence, such as hairs and stains? In addition, as the book progresses, I am realizing that I enjoy Weinberg’s style as a writer. Thus far, she has presented the facts of the case in the way in an informative yet enthralling way. Like any crime show, Weinberg presents this case in such a way that is more than just straight facts. I especially appreciated her simile in the last sentence above.  

Forensics Today