SECTIONS AND SERVICES PROVIDED
FORENSIC LABORATORIES : DEFINITION
They are multidisciplinary science and technological institutions undertaking highly specialized and sophisticated scientific work in the service of crime detection, law and justice.
FUNCTIONS OF FORENSIC LABS
1. Identifying the element of crime
2. Providing investigative leads for a case
3. Linking a crime scene or a victim to a suspect
4. Corroborating or refuting a suspect's statement or alibi
5. Identifying a suspect
6. Exonerating the innocent
7. Proving expert testimony in courts .
UNITS OF A FORENSIC LABORATORY
On the basis of physical evidence to be examined, that labs are divided into various sections as :
1. FORENSIC BIOLOGY
It is a broad unit involving identification and characterization of stains - blood, semen, saliva, urine, sweat ; hair, body tissues, fibers, micro-organisms etc. For specific typing and comparison of botanical materials as plants, wood, etc.
2. FORENSIC SEROLOGY
For identification, analysis and individualization of body fluids and tissues, secretion and excretion. Blood , semen and saliva the the most frequently encountered types. Physical evidence of this type are usually submitted in the form of dried stains on clothing or other materials retrieved from the scene, victim or suspect.
3. PHYSICAL SCIENCE UNIT
It applies principles and techniques of chemistry, physics and geology to the identification and comparison of crime scene evidence. It is staffed with criminalists who utilize tests for the examination of items as diverse as drugs, glass, paint, soil and explosives.
4. BALLISTICS UNIT
The examination of firearms, discharged bullets, cartridge cases, shotgun shells, ammunition of all types, as well as scrapes and impressions on surfaces made by a variety of prying and cutting
The examination of pistols , revolvers, rifles and shotguns determine whether they are in good shape or operable or capable of accidental discharge.
Projectiles recovers from the victim or scene, as well as fire casings are examined to determine whether the ammunition was fired from a particular weapon.
In case where no weapon is recovered, an examination of lands and grooves details may indicate the type of weapon utilized to the exclusion of others.
5.TOOL MARKS ANALYSIS
It involves comparison of impressions created by a hard tool created on softer surface. The impressions left by the tool may show class characteristics, indicating the type of tool utilized and possibly individual characteristics due to wearing of tool surface that could be considered unique to that tool.
6. ANTHROPOLOGICAL EXAMINATION
Frequent identifications are made through comparison of teeth with dental records and x-ray with the corresponding bone structures. Examinations can be conducted to determine whether the skeletal remains belong to an animal or human being. If ascertained as belonging to a human , the race, sex , stature , approximate height ans age at the time of death can also be determined.
7. FORENSIC ENTOMOLOGY
Study of insects and their relation to criminal investigation is forensic entomology. It is used to estimate the time since death. By examining the stages of development of these insects, the time of exposure can be estimated.
8. FORENSIC GEOLOGY
Geological examination provides information on rocks and geological material which can offer important advance to forensic investigation.
9. QUESTION DOCUMENTS
Questioned documents are reported as far back as the roman times, when cases of forged documents were described. Computers, printers and typewriters have added to the activity of the question document experts. Their work includes examination of handwriting, ink, paper, typewriter or printer, impressions , or any other form of writing or printing that may have been used in a case.
10. FORENSIC ODONTOLOGY
It is the study of teeth and their morphology, anatomy and pathological changes due to age. Dentists provide information through examination of teeth and dental prostheses. Victims of a disaster or homicide maybe identified by a comparison of their dental charts, x-rays to the dental evidence from the victim. Bite marks are also examined.
11. TOXICOLOGY UNIT
The purpose of such examination is to examine biological tissues and fluids and organs they affect for the presence of drugs , poisons, alcohol and other toxic substances. The toxicological findings show whether the victim of a crime died or became ill as a result of a drug or poison ingestion, or in a criminal case if the alleged was under their influence during commission of a crime; to find if the dose of certain medicines was prescribed or the victim was poisoned ; to determine if the case was of accidental, homicidal or suicidal poisoning.
12. FINGERPRINT (LATENT) UNIT
Partial or complete finger, palm or footprints chemically lifted or enhanced from various surfaces at crime scenes , weapons and other objects are examined and classified and compared to sets of known or suspected linked sets of prints. This section assists with the identification of the deceased in conjugation with the medical examiner's or coroner's office.
DNA can be extracted from the body tissues , body fluids and body fluid stains recovered as physical evidence in violent crimes. Evidence that can be examined includes known liquid and
dried blood samples, portions of vaginal swabs and extracts , body fluid satined clothes, buckle, undergarments , hair, cigarette butts, used comb, spectacles, cups, glass, tumblers, wrist watches, etc in homicide, sexual assault, etc. As such this technique is capable of directly associating the victim with the suspect, crime scene.
DNA profiles could be also used to solve cases of disputed paternity.
The detection of accelerants in fire debris samples to help prove arson is a common procedure for crime labs. Samples consists of Burns or partially burned wood, carpet, or other materials . Samples of suspected flammable liquids found at a fire scenes are also analyzed.
15.FORENSIC ENGINEERING UNIT
The investigation of accidents involving vehicles in traffic recreational vehicles or air crafts, industrial fire, electrical or meta fatigue accidents brings into picture those who develop and apply principles to the solution of the cause of accidents.