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Forensic Science

  • 04 Sep 2017
Forensic science is the application of science to criminal and civil laws, mainly—on the criminal side—during criminal investigation, as governed by the legal standards of admissible evidence and criminal procedure.
 
Forensic scientists collect, preserve, and analyze scientific evidence during the course of an investigation. While some forensic scientists travel to the scene of the crime to collect the evidence themselves, others occupy a laboratory role, performing analysis on objects brought to them by other individuals.
 
In addition to their laboratory role, forensic scientists testify as expert witnesses in both criminal and civil cases and can work for either the prosecution or the defense. While any field could technically be forensic, certain sections have developed over time to encompass the majority of forensically related cases.

This includes examination of material obtained from vagina, stains from clothing, skin, hair, or other body parts for semen. This is carried out in cases of alleged rape or sexual assault.

Collection of Sample

  • Vagina: Direct aspiration or saline lavage
  • Clothing: When scanned with ultraviolet light, semen produces green white fluorescence. A small piece (1 m2) of clothing from stained portion is soaked in 1-2 ml of physiologic saline for 1 hour. A similar piece of clothing distant from the stain is also soaked in saline as a control.

LABORATORY PROCEDURES

1. MICROSCOPIC EXAMINATION FOR SPERMS

Presence of motile sperms in vaginal fluid indicates interval of < 8 hours. Smears prepared from collected samples are stained and examined for the presence of sperms.

2. ACID PHOSPHATASE

Acid phosphatase is determined on vaginal or clothing samples. Due to the high level of acid phosphatase in semen, its presence indicates recent sexual intercourse. Level of ≥50 U/sample is considered as positive evidence of semen.

3. DETERMINATION OF BLOOD GROUP SUBSTANCES

When semen is positively identified in vaginal fluid or other sample, test can be carried out for the presence of blood group substances in the same sample. The ‘secretor’ individuals (80% individuals are secretors) will secrete the blood group substances in body fluids, including semen.

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4. FLORENCE TEST

This test detects the presence of choline found in high concentration in semen. To several drops of sample, add equal volume of reagent (iodine 2.54 g, potassium iodide 1.65 g, distilled water 30 ml); in positive test rhombic or needle-like crystals of periodide of choline form. False-positive tests can occur due to high choline content of some other body fluids.

Description: New York City has the largest medical examiner’s office in the United States, and the Brooklyn division is the busiest of the five boroughs. Charles A. Catanese received his Forensic Pathology fellowship training in New York, and then worked full time as a Medical Examiner in the Brooklyn office for more than 10 years. He has personally performed more than 4000 autopsies, including over 400 homicides.

Dr. Catanese has worked through several disasters, including TWA Flight 800, AA Flight 587, and more than nine months on the World Trade Center fatalities. He is currently the Chief Medical Examiner of Orange County, New York. Drawing on his wealth of knowledge and experience in solving some of the most difficult cases a forensic examiner could encounter, he assembles hundreds of images from his own work experience to present the Color Atlas of Forensic Medicine and Pathology.
Description: Forensic Pathology: Principles and Practice is an extensively illustrated reference book that contains more than 1800 color photographs accompanied by well-considered text that thoroughly explains representative topics, and also provides abundant, up-to-date references for further reading. This well-written volume uses a case-oriented format to address, explain and guide the reader through the varied topics encountered by forensic pathologists. It will benefit not only the experienced forensic pathologist, but also the hospital pathologist who occasionally performs medicolegal autopsies. Doctors in training and those law enforcement officials investigating the broad spectrum of sudden, unexpected and violent deaths that may fall within the jurisdiction of medicolegal death investigators will also find this an invaluable resource.
  • Large, colorful photographs which beautifully illustrate the concepts outlined in the text.
  • Sample descriptions of pathological lesions which serve to aid pathologists in reporting their findings to law enforcement agencies, attorneys, and others involved in investigations of sudden death.
  • Do and Don't' sections at the end of each chapter which provide guidance for handling the types of cases examined within preceding sections.
Description: Forensic Pathology for Police, Death Investigators, Attorneys, and Forensic Scientists is a forensic pathology book specifically written for professionals who interact with forensic pathologists. The book includes sections that address various general topics which are not normally present in the typical forensic pathology text, such as descriptions of medical, pathology and forensic pathology training, basic anatomy and physiology, an overview of other forensic science disciplines, and autopsy performance. Forensic Pathology for Police, Death Investigators, Attorneys, and Forensic Scientists also covers classic topics in forensic pathology, including death investigation, death certification, postmortem changes, and the entire range of case types, ranging from natural deaths to drug-related deaths to various types of violent death. The text is written in easy-to-understand language, and is complemented by hundreds of high-quality photographs. As an added bonus, a CD containing color versions of all of the photographs shown in the text, as well as hundreds of additional color photographs, is included.

Dictionary:

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