The job of the serologist begins at the crime scene.A forensic serologist extracts DNA evidence from bodily fluids connected with a crime, including blood, semen and saliva. This identifies victims and possible suspects and can be the cornerstone of a criminal conviction.
Tests are also done to determine the blood type and Rh factor, and to figure out which antigens and antibodies are present. These new techniques help to determine whether the blood belongs to any particular suspect.Forensic serology can also be used on other bodily fluids as well. By testing the fluids it is possible to determine that a suspect is definitely not the culprit in the crime, and to give an idea of what type of person might have committed the crime.
Despite how well the crime scene may get cleaned up, even the finest trace of blood can often be detected and further tested. It is often the case that while the perpetrator may scrub down the obvious places, he can still miss between floorboards, under pipes, and inside drains. Merely by pouring water on some tiles at a murder scene and pulling them up wherever the water flowed beneath them, one detective found the only existing trace of the crime--blood.
TOXICOLOGY AND SEROLOGY:
Forensic serology also looks at toxicology factors for evidence of poisoning. It is also used to determine if wildlife has been poisoned.
Presumptive tests:
The Kastle-Meyer Color Test uses a solution of phenolphthalein and hydrogen peroxide on a piece of filter paper, and when blood of any quantity is present, it turns pink. However, it also turns pink in the presence of potatoes or horseradish, so care must be taken at the scene.
Sometimes microcrystalline tests are also performed. The two most often used are the Takayama and Teichmann tests. Both add specific chemicals to the blood to make it form crystals with hemoglobin derivatives. These tests are also sensitive to other materials that may be present in a bloodstain.
Education
- People with a bachelor's or graduate degree in forensic serology or a related field have learned to apply biological science to criminology, including the areas of genetics and DNA analysis, molecular biology, pathology, and metabolic biochemistry. Most forensic serologists work for law enforcement agencies and crime laboratories.
OJ Simpson & Forensic Serology
On the night of June 12, 1994 neighbours were woken by a dog barking. The barking led them to the scene of a bloody crime. Laying in a pool of blood was a woman named Nicole. Near Nicole was her friend. When police arrived and took a closer look, they found that the attack had left Nicole nearly decapitated.
There were many pieces of evidence at the crime scene. Not only was there a blood pool, but there was also a hat and a bloodstained left-handed glove.
After the police made their report, they set off "wake-up calls" to the homicide detectives. The police and homicide detectives met at the scene of the crime and then drove to Simpson's house. While "buzzing" the intercom a detective noticed blood on Simpson's car. Then they saw blood drips going from the car to the front door of his house. More evidence, which was recovered from Simpson's house/bedroom, consisted of a sock belonging to the victim, Nicole, who was Simpson's ex wife. Another piece of evidence was a right-handed glove, retrieved from Simpson's car. It too had blood on it.
Forensic Serology was applied in this case when it came to all of the blood evidence. The blood from the sock was tested and showed that the blood belonged to Nicole. Blood from the right-handed glove was from Simpson and both the victims. The blood trail leading from Nicole's home, to Simpson's car, and then to Simpson's house, in itself, almost proved his guilt. But Simpson's legal team was one of the best and, this ending up being a nine-month long trial, Simpson was later cleared of the murder.
( SOURCE: Forensic Serology Written In Blood...)
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