Collecting Hair Samples

Chapter 18 of Pointing from the Grave continues with Frediani’s trail. Bartick begins questioning the DNA samples that were collected at the scene of the crime. He brings up the hair sample that was picked up by hand, and placed into an old dirty cigarette box. Clearly this is no proper way to handle DNA that can put somebody in prison for the rest of their life. So that got me thinking, “What is the proper way to handle a hair sample?” I went online and found the article that I attached below. It’s pretty interesting check it out. It discusses the ins and outs of collecting DNA samples at a crime scene, particularly hair. Go to the web link below an click on the section titled hair.

http://www.crime-scene-investigator.net/collect.html#3

Collecting Hair Samples

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

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