FREE ESSAY ON CRIME DETECTION

CRIME DETECTION

In recent times, science has provided substantial aid to crime detection. Because anything
in the physical universe has the potential of becoming an item of evidence in an
investigation, a wide variety of procedures may be used in analyzing and interpreting
evidence in a criminal case. These procedures include handwriting analysis, forensic
photography, crime scene documentation, metallurgical investigations, chain of custody,
entomology, and blood spatters. The first thing you do after securing a crime scene is
document it. Always take pictures. They are the best records available. They show the
crime scene as it was found; where objects are in relation to other objects, victims,
rooms, etc. Take notes. Describe the scene, it's over all conditions. Describe rooms,
lights, shades, locks, food; anything that can indicate a time frame, condition of scene
or that might have even the slightest evidentiary significance. Check dates on mail and
newspapers. Diagram the crime scene. Take measurements. Photos are good to show where an
object is in relation to another object, but measurements tell exactly how far. True
handwriting analysis involves painstaking examination of the design, shape and structure
of handwriting to determine authorship of a given handwriting sample. The basic principle
underlying handwriting analysis is that no two people write the exact same thing the
exact same way. Every person develops unique peculiarities and characteristics in their
handwriting. Handwriting analysis looks at letter formations, connecting strokes between
the letters, upstrokes, retraces, down strokes, spacing, baseline, curves, size,
distortions, hesitations and a number of other characteristics of handwriting. By
examining these details and variations in a questioned sample and comparing them to a
sample of known authorship, a determination can be made as the whether or not the
authorship is genuine. Another is, Metallurgical Investigations--examinations make it
possible to identify the source of an item-whether made of metal, plastic, ceramic, or
other material-found at a crime scene, and further, to determine if two similar items
were fractured from each other, the nature of the force causing the fracture, the
direction from which the force came, and the time when the fragments became separated.
Such identification helps trace the evidence to its owner. The metallurgist can also
restore obliterated or altered numbers on objects of any material. 
Mineralogical Investigations is the ?science of mineralogy is also used in crime
detection. The mineralogist studies soil, plaster, cement, brick, concrete, and glass for
any evidence. Mineral analyses have shown that differences may be detected in soil
composition. Soil and dust found on a suspect's clothing and determined to be comparable
to that at the crime scene help to prove the person's presence in that locality.
Toxicology may be defined as the science of poisons special methods of analytical
chemistry have been developed for use in toxicological examinations. The specimens
ordinarily examined in cases of suspected poisoning are tissue samples from vital organs,
blood or urine, food, drink, and the suspected poison itself. Firearms are identified
through microscopic imperfections that are produced inadvertently in gun barrels during
manufacture. Subsequent use and wear contribute further to a weapon's individuality.
Chain of Custody is of paramount importance to any investigation. It is the unbroken
sequence of events that is caused by an item of evidence from the time it is found at the
crime scene to the time it appears in court. Every link in this chain is documented, from
discovery at the crime scene, through evidence gathering, storage, and lab analysis
return to storage, and transfer to court. Every link is documented by date, time, and
handling individual, what was done with the evidence by that individual. If chain of
custody is broken, if the evidence cannot be accounted in one step of its journey from
crime scene to courtroom, it is rendered inadmissible; useless to the case. Blood
spatters help a great deal in reconstructing a crime scene. They can be used to
corroborate or disprove and alibi. They can be used to convict the guilty. There is much
more to it than looking at a stain or spatter and saying, This is where the crime took
place. The patterns of the spatters and the shapes of the individual blood droplets
themselves can tell how the crime was committed. Drops falling from different heights
(i.e. at different speeds) will leave different looking spatters. A drop falling from a
low height of a few inches will leave a small cohesive circle. At greater heights, the
circle will be larger and may even have a 'crown' effect. Hitting a surface at an angle
does even more to disrupt a blood droplet. Perpendicular impact leaves a droplet fairly
uniform, as shown below. A droplet hitting a surface at an angle will bulge out in one
direction, indicating the direction of travel of the droplet. Cast off stains is a result
of blunt force trauma (beating with an object such as a hammer). Pulling back from a blow
produces a blood spatter that indicates direction, by creating an arc of blood droplets.
You can determine the number of blows inflicted by counting the arcs. You can also
determine the orientation of the individuals involved the size of the object used and the
right or left handedness of the assailant. 
Bibliography
encyclopedia