Forensic Science PDF

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QUESTIONS: 1. What is forensic science? -

Forensic itself means forensus = forum. Forum means a public place where judicial proceedings and debate was held.

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In the modern sense, forensics more apply on the courts of law, which forensic science points close to the legal system. It is the application of science and scientific method in the legal system and criminal investigation. Forensic Science involves the collection, preservation, and analysis of evidence suitable for prosecuting an offender in the court of law.

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Importance: To assist investigation in coming up with a finding, To corroborate facts adduced in court, the legal system widely recognizes the role of forensic evidence in the trial of criminal offenders. This is because when scientific techniques and methods are used, there is not much scope for bias or injustice.

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How? Forensic scientists will use scientific knowledge and techniques in interpreting the evidence in connection with criminal and civil, but more on criminal cases as ot roles more on neutral and less injustice.

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In criminal, forensic science helps in proving the guilt or innocence of the defendant by corroborate facts and adduce in court.

2. What are the scopes in forensic science? -

Forensic Biology/DNA -

DNA profiling helps to identify or confirm an unidentified person, or to eliminate suspects from a list of accused.

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Most commonly used biological evidence for DNA profiling : blood, saliva, semen, skin, urine, hair

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However, DNA fingerprints are usually never used as single piece of evidence

Forensic Odontology -

Helps in the identification of victims when the body is left in an unrecognizable state.

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By examination of teeth, alignment, and overall structure of the mouth

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Forensic dentists or odontologists aid in the comparative identification of a person by examining the development and anatomy of the teeth including any restorative dental corrections such as filling. It is often applied to criminal investigations for bite mark analysis.

Forensic Toxicology -

Analysis of biological samples to check for the presence of toxins and drugs

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Information about nature of substances, and determine whether the quantity of substances are normal or exceed the permissible level

Forensic Anthropology -

Examination of compromised human remains or skeleton to help determine the age, gender, and ancestry.

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Also help establish the time since death by identifying and examining injuries

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Identifying victims, especially in cases where bodies are beyond recognition

Forensic Pathology -

Helps determine the cause of death by examining a corpse

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Eg: identification of wound patterns can help determine the weapon used

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Forensic pathologists can examine exit and entry wounds in death pertaining to the use of firearms or other projectiles

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Therefore, they can draw crucial inference on whether the death is natural, criminal or accidental

Cyber Forensic -

Involves analysis of evidence found in computers and digital storage media like pen drives, hard disk, etc

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Its major objective is identifying, preserving, recovering, analyzing, and presenting facts and opinions about the digital information

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Mostly used for investigation of cyber crimes, also widely used in civil proceedings

Ballistics -

Deals with motion, behaviour, dynamics, angular movement and effects of

projectiles. Eg: bullets, rockets, missiles, bombs -

Examination of bullet found at a crime scene can reveal what type of gun was used and whether it is associated with any crime in the past

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Mainly used in criminal investigations

Controlled Substances -

Controlled substances is chemicals that are legally recognised as having potential for abuse

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This includes “street drugs” such as ecstasy or heroin, and prescription drugs such as oxycodone

Impression and pattern evidence -

Impression evidence: evidence created when two objects come in contact with enough force to create “impression”. This could involve 2D impressions such as fingerprint or 3D such as marks on bullets.

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Pattern evidence: identification and analysis of additional information within an impression

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Impression and pattern evidence when used in conjunction can help establish vital links between a suspect/tool to a crime scene

Trace evidence -

It derives its name from its tendency to be easily transferable between objects, people or environment during a crime

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Eg: fibers, soil, hair, gunshot residue, wood, pollen

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Plays a pivotal role in establishing a prime link between suspect and victim

3. What are relevant sections that govern the evidence of an expert in Malaysia? -

Section 45(1) of Evidence Act 1950; when the court has to form an opinion upon a point of foreign law or of science or art, as to identity or genuineness of handwriting or finger impressions, the opinions upon that point of persons specially skilled in that foreign law, science or art, or in questions as to identity or genuineness of handwriting or finger impressions, are relevant facts.

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Section 45(2) of Evidence Act 1950; such persons are called experts.

4. What is a crime scene? -

A crime scene is any physical scene, anywhere that may provide potential evidence to an investigator. In other words, it is any place that relates with the commission of the crime. It can be a person’s body, any type of building, vehicles and open space.

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Crime scenes can be divided into 2 which are primary crime scene and secondary crime scene. Primary crime scene is the site of the original for first criminal activity. For example, A killed B at B’s bedroom, so B’s bedroom is the primary crime scene. Meanwhile, the secondary crime scene is the subsequent crime scene. For example, the murder weapon used by A found at a playground, 2km from B’s house. So the playground is the secondary crime scene.

5. Explain the Locard’s exchange principles -

In the early 20th century, Dr. Edmond Locard, (French police officer) who is a forensic science pioneer in France, formulated the theory which states, “Every contact leaves a trace”. This became known as Locard’s exchange principle and is the basis for all forensic science as we know it today.

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He noticed that the exchange of materials is the basis of modern forensic investigation. It is emphasized that every contact you make with another person, place, or object, enters or exits the environment results in an exchange of physical materials thus leaving a trace.

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The logic behind this principle is that it allows the investigators to link suspect to victims, to physical object and to the scenes.Using this principle, for example, forensic scientists can determine where a suspect has been by analyzing trace evidence (any small piece of evidence), such as fibers on clothing, hair in a car or gunk on the soles of shoes.

6. Who will be at the crime scene? -

Four categories of people may be at a particular crime scene:

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Police officer who usually has the duty to safeguard the crime scene.

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Forensic officer helps with the examination of the dead body.

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Complainant/victim to direct the police what actually happened

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Medical examiner

7. What are the steps taken in processing a crime scene? ·

Securing the crime scene To identify the extent of the crime scene and those without authorization could not access the crime scene, so that none of the objects are removed and there is no contamination with the crime scene.

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Separating the witness

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Scanning the scene The forensic will examine the crime scene thoroughly.

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Seeing the scene There will be photographers, videographers, sketchers to capture the crime scene very specifically.

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Sketching the scene This is one of the documentations of the crime scene, where the investigators will need to provide a sketch of the crime scene.

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Searching the evidence This is intensive search of the scene for physical evidence on the crime scene.

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Securing and collecting evidence This is for preservation of the evidence. One individual should be designated as the evidence collector to ensure that the evidence is collected, packaged, marked, sealed, and

preserved in a consistent manner. No item of evidence will be missed, lost, or contaminated if only one person has the obligation for this collection of evidence. This is very important to ensure that the chain of evidence is not broken. Simplified version = (1. Securing crime scene 2. Examination of crime scene 3. Documentation of crime scene 4. Collection and preservation 5. Maintaining chain of evidence) 8.

What are types of search pattern that a forensic officer can use in conducting his search at the crime scene?

Upon the crime scene being secure, the forensic officer will then begin examining the crime scene. There are several search patterns that the forensic officer can use: a) Spiral Search Pattern -

Inward spiral: The forensic officer will start at the perimeter of the scene and work towards the centre. Spiral patterns are a good method to use and when there is one officer on the scene. This is rarely used.

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Outward spiral: The officer starts at the centre of the scene/body and works outward.

b) Parallel Search: All members will form a line. They will walk in a straight line, at the same speed and pace, from one end to another of the crime scene.

c) Grid Search: A grid search is simply two parallel searches, offset by 90 degrees, performed one after another.

d) Zone Search: The team leader will divide the crime scene into sectors, and each team member will take one sector to conduct the search. Team members may then switch sectors and search again to ensure complete coverage.

9. What is a fingerprint?

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Fingerprint is the impression left by the finger of a human containing the friction skin on fingers and palm from the first joint of the hand to the nail bed of fingers. Each fingerprint forms ridges, the appearing part and furrows, being the deep line which will not appear. This friction of skin containing their individual ridges and furrows are so unique for identification of an individual as it varies from one another, thus fingerprint is used as a means of identification.

10. Name all patterns that can be found in a fingerprint? -

According to Galton’s system, fingerprints can be divided into 3 which are arches, loops and whorls.

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Arches pattern is where the ridges enter on one side and exit on the other side of the finger. It can be further divided into Plain Arch and Tented Arch. It creates a wave-like pattern and includes plain arches and tented arches. Tented arches rise to a sharper point than plain arches. Arches make up about 5 percent of all pattern types.

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Loops pattern is where one or more ridges enter one side and exit the same site the ridge entry. Loops can be sub-divided into Ulnar Loop (right thumb) and Radial Loop (left thumb).

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Whorls pattern is where it forms circular or spiral patterns as the ridge makes a complete circuit. There are four groups of whorls: plain (concentric circles), central pocket loop (a loop with a whorl at the end), double loop (two loops that create an S-like pattern) and accidental loop (irregular shaped). Whorls make up about 35 percent of pattern types.

11. How can a fingerprint be processed and identified? (Hani) A fingerprint analyst will examine the points which are known as focal points. Each individual has a unique focal point on their fingerprint making fingerprints an outstanding method for individual identification.

Fingerprint impressions are classified into three basic types:-

Latent,Visible & Plastic Techniques used to enhance the latent fingerprints depends on the type of surface being examined. There are 2 type of surfaces:-Porous (Soft and absorbent surface- eg. Paper, cloth) -Non-porous (Hard and non-absorbent surface- eg. Plastic, glass) Techniques used on a porous surface. 1. Iodine fuming -a technique for visualizing latent print by exposing them to iodine vapour 2. Ninhydrin -a chemical reagent used to develop latent print by reacting with amino acids in perspiration -Ninhydrin causes prints to turn a purple color, which makes them easily photographed 3. Physical developer -a silver nitrate-based reagent formulated to develop latent print on porous surfaces Techniques used on non-porous surfaces. 1.

Fingerprints powders

-gray or black powders are two most common dusting materials used to develop latent prints. -when the prints appear, they are photographed and then lifted from the surface with clear adhesive tape. -the lifting tape is then placed on a latent lift card to preserve the print 2.

Super Glue Fuming

-this process involves exposing the object to cyanoacrylate vapors. -the vapors (fumes) will adhere to any prints present on the object allowing them to be viewed with oblique ambient light or a white light source. 3.

Cyanowand

-it is a small handheld wand that makes a cyanoacrylate fuming

-the wand heats a small cartridge that contains cyanoacrylate and vaporize -the fumes will interact with amino acid contained in the fingerprint 4.

Alternate Light Source (ALS)

-these are laser or LED devices that emit a particular wavelength, or spectrum, of light which can identify physiological fluids

Fingerprint analysis -usually performed by law enforcement agencies or crime laboratories. The fingerprint analysis process:1. Analysis -assessing a print to determine if it can be used for a comparison. -if the print is not suitable for comparison because of inadequate quality or quantity of features, the examination ends and the print is reported as not suitable. -if the print is suitable, the analysis indicates the features to be used in the comparison and their tolerances 2. Comparisons -performed by an analyst who views the known and suspect prints side-by-side. -the analyst compares minutiae characteristics and locations to determine if they match. 3. Evaluation -the examiner ultimately decides if the prints are from the same source (identification or individualization), different sources (exclusion) or is inconclusive. -inconclusive results may be due to poor quality samples, lack of comparable areas, or insufficient number of corresponding or dissimilar features to be certain. 4. Verification -another examiner will independently analyze, compare and evaluate the prints to either support or refute the conclusions of the original examiner. -the examiner may also verify the suitability of determinations made in the analysis phase

12. What is physical evidence? (Alia) - Physical evidence is any material object, introduced in a trial, intended to prove a fact in issue based on its demonstrable physical characteristics. - The term physical evidence involves any physical entity that can furnish some degree of proof or disproof where it establishes a link between a crime and its offender or crime and its victim. - Physical evidence can conceivably include all or part of any object and it is measurable with respect to size, shape, characteristics and direction. - There are many types of physical evidence which are bodily fluids , blood, hairs and fibers, fingerprints, footwear impressions,tool marks,firearms,documents or any other item linking a suspect to a crime.

13. What does a forensic officer must observe when collecting evidence? (Wina) -

Upon completion of the crime scene documentation and intensive search of the scene for physical evidence, then the collection process can begin.

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Prior to this, a person would be designated as the evidence collector to ensure that the evidence is collected, packaged, marked, sealed, and preserved in a consistent manner. Consequently, no item of evidence will then be missed, lost, or contaminated.

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However, there are a few things that a forensic officer could observe throughout the collection which are - Starting off the collection process with the collection of the most fragile or most easily lost evidence (despite having no rigid order for collection of the evidence) - Reason: Some types of evidence, by their nature, should be given some priority of order.

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The officer must proceed with the documentation immediately if there are some items of evidence moved or repositioned because of the location within the crime scene.

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Ensure that each evidence is kept separated from one another (To prevent contamination)

- The forensic officer must ensure that every evidence that was collected is properly stored, bag and tag. They must be also well sealed and logged with the relevant info including i.

Description of the item

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Identity of the collector

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Time and date

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Location of the item found

14. Explain how a latent impression can be collected and what method can a forensic officer use in collecting it? •

Collecting latent impressions can be carried out by dusting a smooth or non-porous surface with fingerprint powder (black granular, aluminum flake, black magnetic, etc.). If any prints appear, they will be photographed and lifted from the surface with clear adhesive tape. The lifting tape is then placed on a latent lift card to preserve the print.

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A variety of fingerprint powders, brushes and tapes are needed for this method. The science behind this is that the particles in the fingerprint powder will stick to the moisture left on ridges in the fingerprint.

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The print is affixed to one side of the lift card, while the other side will record the date of the lift, which investigator or technician who lifted the print, the agency, department case number and location of the lift.

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Different law enforcement departments employ different policies regarding how prints are to be lifted, mounted and photographed.

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Fingerprints also can be lifted from the victim’s skin. It requires a skilful and experienced person to lift latent impressions on various surfaces.

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However, bear in our mind that the fingerprint powder used can contaminate the evidence and ruin the opportunity to perform other techniques that could turn up a hidden print or additional information.

15. Explain the process of collecting, marking and packaging a particular evidence? -

In collecting the evidence, there are certain types of evidence require different methods of collection and storage. -

The most common method is latent impressions which is the mechanical method.

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