Blood evidence at the scene

(Hahahahahaha, while I was trying desperately to get blood to my crime scene I ended up cutting my hand on something sharp and ended up leaving a bloodtrail)

Blood from the perpetrator. Unlike collecting it from the bathroom sink, toilet, shower, etc. this sample would have to be cut out of the rug and taken with in a plastic evidence bag. I once had a teacher that told me "If it is mobile, then take the whole thing with you to the lab" this is blood from a human because i watched it pour out of my hand.

but i would normally test it with a cotton swab and the blood test.  and bag it in plastic bag or well ventilated container.

dna in progress

Explain in a new entry about the nature of blood, what makes up blood, how and what are blood characteristics. Document how blood is typed and what typing of blood shows us which has a direct affect on Forensic Science.

What questions MUST a criminalist answer when examining dried blood samples?

Explain Blood color testing and Blood origin testing. How does the criminalist individualize bloodstains?

what makes up blood: 

Blood is typed as type A, B, AB, and O (but there are more breakdowns, positive and negative and the rhesus factor). On type A blood, there is an A antigen, on type B a b antigen, AB has neither the a and b antigen, and type O has both a and b antigen. DNA is vital evidence in resolving violent crimes and sex offenses. DNA is impartial, incriminating the guilty and exonerating the innocent. 

when dealing with dried blood, the criminalist must answer the following questions:
1) Is it blood?
2) From what species did the dried blood originate?
3) If the blood is human, how closely can it be matched with a particular individual?


Blood  color testing was commonly known as the benzidine color testing. but since benzidine is a carcinogen, it obviously is discontinued. Phenolphthalein has been substituted  (kastle-meyer color test).
both tests are based on the observation that hemoglobin possesses peroxidase like activity. Peroxidase are enzymes that accelerate the oxidation of several classes of organic compounds when combined with peroxides.

once the stain has been characterized as bllod, the serologist determines whether the blood is of human or animal origin. the standard test for this is called the precipitin test. precipitin tests are based on the fact that when animals(usually rabbits) are injected with human blood, antibodies form that react with the invading human blood to neutralize its presence. the investigator can recover these antibodies by bleeding the animal and isolating the blood serum which contains antibodies that specifically react with human antigens.

traces

After examining the contents of the vacuum bag, that were collected in the office, I found what looked like dirt, some strands of thread, black hair, a small fish hook, some plastic fibers, white hairs and nail (possibly fingernail) clippings.  

                The homeowner says this office is used for bookkeeping and fly tying for the fishing business her husband owns, the thread matched thread the homeowner provided, the white hairs matches the hairs from the homeowners, and she says her husband usually clips his fingernails when he is down in the office.  There were also dirt and black hairs which were unknown to the homeowners.

                I also vacuumed a rug in the bathroom. On which I have found more dirt, more black hairs, toilet paper balls, green fibers (possibly from the rug), plastic wrapping (possibly from the first aid kit that was all over the floor, will check for prints).

                Both areas have unknown dirt and black hair samples. The dirt looked like it was dragged in on a shoe, because it was spaced like the tread on the soles of shoes.

                I collected the shoes with a matching tread from our suspect in question. They match the soles from the cast imprint in the dirt behind where the crime scene took place. I notice in the soles of the shoes, tiny pebbles, fragments of glass attached to the glass is a green fiber, similar (to the eye) to the green rug in the bathroom of the house and it looks like blood on the glass, which will need further confirmation from the lab.

            Just by naked eye examination, these shoes appear to be a match to the shoe prints found in and around the crime scene, trace will tell us if they are an exact match to the crime scene. Our unknown just became suspect #1!

(no pictures this week as my week was inconspicuous and blotchy and unavailable, and unattainable)   

pod 6 option 3

Option 3:

Answer these questions in a new entry:

1. Can the body area of which the hair originated be determined?
2. Can racial origin be determined from the hair?
3. Can age or sex (gender) be determined?
4. Can it be determined if the hair was removed by force?
5. What effect has the evolution of Mitochondrial DNA testing had on hair analysis?

Yes the area can be determined as to which part of the body it came from, whether it is scalp, body, or pubic. Some parts of the body have shorter, darker hair, other parts have thinner, hair, and still others have medium type hair.

Racial origin can be determined. here are two examples of racial origin:
1)  African descent
          - kinky with dense uneven pigment
          -flat to oval in shape
2) European/Caucasian
          - straight or wavy fairly evenly distributed pigment
          - oval to round shape

Age can be determined by the fact that some people dye their hair, it turns white and/ or gray. And sex can be definitively determined  accomplished through the staining of sex chromatin in the cells found in the follicular tissue.


Presence of follicular tissue on root indicative of forcible removal. to determine also if hair was forced out or fell out, Naturally shed hairs, such as a head hair dislodged through combing, display undamaged, club-shaped roots. A hair forcibly removed from the scalp will exhibit stretching and damage to the root area or may have tissue attached.


Recent major breakthroughs in DNA profiling have extended this technology to the individualization of human hair.  The probability of detecting DNA in hair roots is more likely for hair being examined in its anagenor early growth phase as opposed to its catagen (middle) or telogen (final) phases. Often, when hair is forcibly removed a follicular tag, a translucent piece of tissue surrounding the hair’s shaft near the root may be present. This has proven to be a rich source of nuclear DNA associated with hair.


Mitochondrial DNA can be extracted from the hair shaft. Mitochondrial DNA is found in cellular material located outside of the nucleus and it is transmitted only from the mother to child.  As a rule, all positive microscopic hair comparisons must be confirmed by DNA analysis.

(helped from http://chemistry.armstrong.edu/nivens/Forensics/CHEM%204600/CHEM%204600%20Hair,%20Fiber%20Paint%20Chapters%2011,12,13,%2014.pdf)

evidence

Jack the Ripper

In England, 1888, it was no longer safe to be walking the streets of London's Whitechapel. A killer, given the nickname of 'Jack the Ripper', was stalking and murdering prostitutes in the area - five to begin with, between late August and early November, 1888, but would eventually kill a total number of seven women. 'Jack the Ripper' would murder the women, before partially dissecting them and leaving their bodies to be found by passing people. This case was the first case that psychological profiling was used in an attempt to catch a serial killer. A police surgeon by the name of George B. Phillips first noticed that each of the murdered victims had their organs removed with precision that could only be achieved by someone with training in the medical or butchery industry. Despite following these observations and the fact that the police received several taunting notes signed 'Jack the Ripper', the killer was never caught. Some notable suspects that later investigations led to included Walter Sickert, an Impressionist painter who released paintings of murdered prostitutes 20 years later, Robert Stephenson, the army surgeon/occultist/magician and another man by the name of Thomas Cutbush. But to this day, the identity of Jack remains a mystery.

They have made a boardgame from this monstrous murder spree of an unknown and uncaptured individual, letters from whitechapel. 

the fact that he/she was specifically trained in surgery/butchery and that they had letters signed by jack the ripper were two huge pieces of the unsolved puzzle. to this day there are people out there still trying to find this murder, but most likely never will. but good luck!