Chapter 2 Flashcards
Police is usually inclined to be niggardly in taking samples. This mistake should be avoided.
Sufficiency of the specimen
Chemical findings are used in:
- Convicting the guilty; and
- Clearing the innocent
Keep a full, neat and clear record or everything seen and done.
Take notes
It is the second step in the investigating a crime scene. It will help identify possible items of evidentiary nature, point of entry and point of exit, and getting the general layout of the crime scene.
Examine
Guiding principles that must be observed in the practice of Forensic Chemistry
a) Sufficiency of the specimen
b) Standard for comparison
c) Maintenance of individuality
d) Labeling and sealing
It is a second person associated with committing a crime.
Accomplice
The results of the examination conducted will be communicated to the requesting party in the form of a written report which must include an enumeration of the articles received for examination with detailed description of the packing, sealing and labeling, date of receipt and from whom received the purpose of the examination, the findings and conclusion. The findings should include a brief but sufficient record of all significant facts noted during the examination.
Communication of Result
It is the third step in the protocol. It involves creating a pictorial record of the scene and record items of possible evidence.
Photograph
Types of Scientific Evidence
a) Real or Autoptic Evidence
b) Testimonial Evidence
c) Experimental Evidence
d) Documentary Evidence
All identifications, definite or indefinite, are made consciously or unconsciously on the basis of probability.
Law of Probability
Each evidence must be collected and preserved as a separate sample. There must be no mixing or intermingling of unknown to known.
Maintenance of individuality
Everything changes with the passage of time.
Law of Progressive Change
Crime Scene Protocol
- Interview
- Examine
- Photograph
- Sketch
- Process
Types of evidence
a) Testimonial Evidence
b) Physical Evidence
c) Trace Evidence
Scope of Forensic Chemistry
- Includes the chemical side of investigation
- Analysis of material leading to legal proceedings
- Not only purely chemical questions but aspects of Forensic Science
It refers to the utilization of UV and IR Spectrophometry.
High Precision Method
The first step in the examination of an article is to scrutinize it carefully and write down in the laboratory notebook a complete description of its external appearance including the manner in which it is secured and particulars of the sealing.
Actual Examination of Specimen
Characteristics of Tools and Techniques Used
- Sensitivity
- Specificity
- Rapidity
It is the original location of the crime or accident.
Primary Crime Scene
It is the fourth step in the protocol. Demonstrate the layout of the crime scene or to identify the exact position of the deceased victim or evidence within the crime scene.
Sketch
Good work cannot be buried, therefore take all the time necessary to make the case complete, no matter how urgent it may appear or how pressing others may be of the result; it is generally possible to adjourn a case if the work cannot be finished in time (Urbano, 2008).
Go slowly
Types of Witness
a) Ordinary Witness
b) Expert Witness
Six Golden Rules
- Go slowly
- Be thorough
- Take notes
- Consult others
- Use imagination
- Avoid complicated theories
It is most important that whenever possible the chemist should personally collect the entire specimen necessary for the examination.
Collection or Reception of the Specimen to be Examined
It is any physical location in which a crime has occurred or is suspected of having occurred.
Crime Scene
It enables and deductions to be made from slender and incomplete premise is very useful (Urbano, 2008).
Use imagination
Methods of Analysis
- Wet Method
- High Precision Method
If the evidence in question is found in the presence of foreign substance, a sample of the foreign substance must be submitted for analysis.
Standard for comparison
Types of Examination Used
- Qualitative Examination (What)
- Quantitative Examination (How much)
It is a method of analysis that requires much time and effort.
Wet Method
It refers to evidence that is found at a crime scene in small but measurable amounts.
Trace Evidence
This refers to the application of Chemical Principles in the examination of physical evidences. It is Chemistry applied in the elucidation of legal problems (Corpuz, 2015).
Forensic Chemistry
The written report of the chemist is usually supplemented at a later date by oral evidence if the case is brought to court or fiscal’s office.
Court Appearance
It is a means, sanctioned by law, of ascertaining in a judicial proceeding the truth respecting a matter of fact.
Evidence
Roles of Forensic Chemistry
- Speedy Investigation
- Solution of Crimes
It is the branch of Chemistry that deals with the application of chemical principles in the solution of problems that arise in connection with the administration of justice (Urbano, 2008).
Forensic Chemistry
The analysis can be no better than the sample analyzed.
Principle of Analysis
Basic Forms of Evidence
a) Direct Evidence
b) Circumstantial Evidence
c) Hearsay Evidence
Only “likes” can be compared.
Principle of Comparison
This is any material items that would be present on the crime scene or the victims.
Physical Evidence
It would be any witnessed accounts of an incident or crime.
Testimonial Evidence
Evidence will have no value in court in spite of the good report of the expert if the specimen cannot be identified and possibility of tampering excluded.
Labeling and sealing
It is the means sanctioned by law, of ascertaining in a judicial preceding the truth respecting a matter of wherein scientific knowledge is necessary (Corpuz, 2015).
Scientific Evidence
The simplest explanation is usually the right one.
Avoid complicated theories
It is an evidence which is addressed to the senses of the court.
Real or Autoptic Evidence
It refers to one who states facts and may not express his opinions or conclusion.
Ordinary Witness
It is a person thought to be capable of committing a crime.
Suspect
It is the last step in the protocol. Crime scene technician will process the crime scene for evidence, both physical and testimonial evidence.
Process
Principle Used in Forensic Chemistry
- Law of Individuality
- Law of Progressive Change
- Principle of Comparison
- Principle of Analysis
- Law of Probability
It is an evidence that comes from people, e.g. testimony of an expert witness in court.
Testimonial Evidence
It is an evidence that which the senses perceive. Any fact to which a witness testifies based on what he saw, heard, smelled, touched or tasted.
Direct Evidence
It is one who testifies in court and has personal knowledge or experience of something.
Witness
It is any written evidence presented by an expert in court.
Documentary Evidence
Factors Contributing to the loss of Physical Evidence
a) Lack of precautions preventing tampering of specimen
b) Failure in preservation
c) Failure in transport of specimen
d) Failure in identifying the specimen
e) Improper packing of specimen
Two types of crime scene
a) Primary Crime Scene
b) Secondary Crime Scene
Every object, natural or man – made has an individuality which is not duplicated in any other object.
Law of Individuality
Stages in the Practice of Forensic Chemistry
- Collection or Reception of the Specimen to be Examined
- Actual Examination of Specimen
- Communication of Result
- Court Appearance
It is a kind of evidence which seeks to establish a conclusion by inferences from proved facts. An evidence which establishes a fact or circumstance from which the court may infer another fact at issue.
Circumstantial Evidence
It is the first step in processing a crime scene is to determine what allegedly happened, what crime took place, and how was the crime committed. May not be factual information. It gives the investigators a place to start.
Interview
It is a statement of where a suspect was at the time of a crime.
Alibi
It is an alternated location, such as where additional evidence may be found.
Secondary Crime Scene
This refers to one who possesses a special skill, be it in art, trade or science or one who has special knowledge in matters not generally known to men or ordinary education and experience.
Expert Witness
It is a statement made by a witness on the authority of another and not from his own personal knowledge or observation.
Hearsay Evidence
Make a careful and minute examination of everything and do not be satisfied with a qualitative analysis if a quantitative one be possible; it always pays to do too much rather than too little and it is difficult to foresee what will or will not be requires in court (Urbano, 2008).
Be thorough
An expert witness may be required to perform certain experiments to prove a certain matter of fact.
Experimental Evidence
