CHAPTER 2 Flashcards
-The application of Chemical Principles in the examination of physical evidences.
FORENSIC CHEMISTRY
-embraces a large and diversified field.
FORENSIC CHEMISTRY
-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.
FORENSIC CHEMISTRY
-It is Chemistry applied in the elucidation of legal problems.
FORENSIC CHEMISTRY
–study of everything or study of matter
FORENSIC CHEMISTRY
It includes not only the chemical side of criminal investigation with which it is generally associated with the public mind but also the analysis of any material the quality of which may give rise to legal proceedings.
FORENSIC CHEMISTRY
is not limited to purely chemical questions involved in legal proceedings.
FORENSIC CHEMISTRY
CHEMICAL FINDINGS ARE USED IN:
- CONVICTING THE GUILTY
- CLEARING THE INNOCENT
It has invaded other branches of forensic sciences notably legal medicine, ballistics, questioned documents, dactyloscopy and photography.
FORENSIC CHEMISTRY
-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
ROLES OF FORENSIC CHEMISTRY
- SPEEDY INVESTIGATION
- SOLUTION OF CRIMES
-Unless this is done, something essential to the elucidation of the problem may be omitted and in some cases questions regarding the collection and transit of the specimen are raised during the trial.
COLLECTION OR RECEPTION OF THE SPECIMEN TO BE EXAMINED
Includes the chemical side of investigation
Forensic Chemistry
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
-In the collection of specimen the following guiding principles 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
COLLECTION OR RECEPTION OF THE SPECIMEN TO BE EXAMINED
-In the collection of specimen the following guiding principles 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
–collect as many evidence as you can dahil its for the benefit of the case
SUFFICIENCY OF THE SPECIMEN
– Police is usually inclined to be niggardly in taking samples.
SUFFICIENCY OF THE SPECIMEN
–this is the main concern among the others in the Stages in the practice of forensic chemistry
COLLECTION OR RECEPTION OF THE SPECIMEN TO BE EXAMINED
-This mistake should be avoided.
SUFFICIENCY OF THE SPECIMEN
–not sufficient to yield the result
–there is a required sample kasi kung hindi masusunod ay magkakaroon ng problem
SUFFICIENCY OF THE SPECIMEN
– 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
–secure the substance first
STANDARD FOR COMPARISON
– Each evidence must be collected and preserved as a separate sample.
MAINTENANCE OF INDIVIDUALITY
-There must be no mixing or intermingling of unknown to known.
MAINTENANCE OF INDIVIDUALITY
–protection of the alleged and the court
–maintain the integrity, make sure it is not a product of planted evidence (DOCTRINE OF FRUIT OF THE POISONOUS TREE)
LABELING AND SEALING
– 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
a) Scrutinize, document complete description of external appearance, manner of collection and secured.
b) Take photographs if possible.
c) Weigh, measure, record.
ACTUAL EXAMINATION OF SPECIMEN
–every evidence is not the same, if you saw hair in different scene, you need to collect them and place it in the separate container
–“evidence are like an individual”
MAINTENANCE OF INDIVIDUALITY
-The _______ 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.
COMMUNICATION OF RESULT
– Evidence will have no value in court inspite of the good report of the expert if the specimen cannot be identified and possibility of tampering excluded.
LABELING AND SEALING
- unang manonotify dahil they are following the command responsibility or the scalar chain
CHIEF/HEAD
-The findings should include a brief but sufficient record of all significant facts noted during the examination.
COMMUNICATION OF RESULT
-it is generally possible to adjourn a case if the work cannot be finished in time.
GO SLOWLY
– 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
SIX GOLDEN RULES
a. GO SLOWLY
b. BE THOROUGH
c. TAKE NOTES
d. CONSULT OTHERS
e. USE IMAGINATION
f. AVOID COMPLICATED THEORIES
-In this, the witness must be composed and as much as possible avoid being irritated by upbraiding of the opposite counsel.
COURT APPEARANCE
– 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;
GO SLOWLY
– Make a careful and minute examination of everything and do not be satisfied with a qualitative analysis if a quantitative one be possible;
BE THOROUGH
–always remember the “life of the suspect or the victim”
–the more na nagmamadali, mas lalong magkakamali
GO SLOWLY
-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.
BE THOROUGH
– Many cases will lead the expert into paths with which he is not familiar, and when this happens he should _____ who are most likely to know.
CONSULT OTHERS
– Keep a full, neat and clear record or everything seen and done.
TAKE NOTES
The ________ may win or lose a case on the physical evidence presented by the investigator.
prosecuting fiscal
– It enables and deductions to be made from slender and incomplete premise is very useful.
USE IMAGINATION
–you already have the beforehand information kaya you need to use critical thinking
–this is considered as “positive aspect”
USE IMAGINATION
– The simplest explanation is usually the right one.
–the more complicated, mas prone to problems
AVOID COMPLICATED THEORIES
However, these pieces of ______ that are very valuable become lost as fast as prosecutive value is concerned.
evidence
TYPES OF EXAMINATION USED
a. QUALITATIVE EXAMINATION
b. QUANTITATIVE EXAMINATION
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
-examination that questions what?
QUALITATIVE EXAMINATION
-examination that questions how much?
QUANTITATIVE EXAMINATION
METHODS OF ANALYSIS
a. WET METHOD
b. HIGH PRECISION METHOD
– This refers to the utilization of UV and IR Spectrophometry.
HIGH PRECISION METHOD
– Requires much time and effort.
WET METHOD
TECHNIQUES USED IN FORENSIC CHEMISTRY
a. MICROSCOPY
b. PHOTOGRAPHY
c. INVISIBLE RAYS
d. CHROMATOGRAPHY
e. ELECTROPHORESIS
f. SPECTROGRAPHY
g. LASER TECHNIQUE
h. MASS SPECTROMETRY
i. SPECTROPHOTOMETRY
j. NEUTRON ACTIVATION ANALYSIS
k. XRD (X-ray Diffraction)
l. DNA TYPING AKA DNA PROFILING
m. FORENSIC ENTOMOLOGY
n. ATOMIC ABSORPTION SPECTROMETRY (AAS)
– This refers to the technical field of using microscopes to view samples & objects that cannot be seen with the unaided eye (objects that are not within the resolution range of the normal eye).
MICROSCOPY
– This refers to biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis.
CHROMATOGRAPHY
– This refers to the use of light such as UV, IR, X-ray and etc. for the identification and evaluation of pieces of evidence.
INVISIBLE RAYS
– (Preservation of evidence) this refers to the study concerning the duplication of images through the action of light, upon sensitized materials (photographic paper or film) with the aid of mechanical device (camera) and its accessories, and the chemical processes (film developing and printing) involved therein.
PHOTOGRAPHY
-Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase.
CHROMATOGRAPHY
-This refers to the technique of an optical device for breaking light down into a spectrum and recording the results photographically.
SPECTROGRAPHY
– This refers to laboratory technique used to separate DNA, RNA, or protein molecules based on their size and electrical charge.
ELECTROPHORESIS
is used to move molecules to be separated through a gel.
electric current
-Pores in the gel work like a sieve, allowing smaller molecules to move faster than larger molecules.
ELECTROPHORESIS
-The conditions used during this can be adjusted to separate molecules in a desired size range.
ELECTROPHORESIS
– This refers to methods of sampling and chemical analysis serve as less destructive means to analyze precious sample specimens by requiring less material per measurement and providing superior spatial resolution compared to traditional solution and/or bulk methods of chemical analysis.
LASER TECHNIQUE
– This refers to a method used to estimate the level of an analyte in solution.
SPECTROPHOTOMETRY
– This refers to the field dealing with separation and analysis of substances according to the masses of the atoms and molecules of which the substance is composed.
MASS SPECTROMETRY
-It relies on the principle that materials absorb light of a certain wavelength as it passes through the solution.
SPECTROPHOTOMETRY
states that the amount of light of a particular wavelength absorbed by a substance across a constant distance (lightpath) is proportional to the concentration of that substance.
Beer’s Law
– This refers to a rapid analytical technique primarily used for phase identification of a crystalline material and can provide information on unit cell dimensions.
XRD (X-ray Diffraction)
– This refers to a process used for determining the concentrations of elements in a vast amount of materials.
NEUTRON ACTIVATION ANALYSIS
-Beer’s Law states that the amount of light of a particular wavelength absorbed by a substance across a constant distance (lightpath) is proportional to the concentration of that substance.
SPECTROPHOTOMETRY
-It allows the precise identification and quantification of the elements, above all of the trace elements in the sample.
NEUTRON ACTIVATION ANALYSIS
relies on excitation by neutrons so that the treated sample emits gamma – rays.
NEUTRON ACTIVATION ANALYSIS
has applications in chemistry but also in other research fields, such as geology, archeology, medicine, environmental monitoring and even in the forensic science.
NEUTRON ACTIVATION ANALYSIS
-The analyzed material is finely ground, homogenized, and average bulk composition is determined. (Dutrow and Clark, 2020)
XRD (X-ray Diffraction)
– This refers to a laboratory procedure that detects normal variations in a sample of DNA (deoxyribonucleic acid).
DNA TYPING AKA DNA PROFILING
is most often used to establish identity, parentage, family relationship and appropriate matches for transplantation of organs and tissues.
DNA TYPING AKA DNA PROFILING
– This refers to the study of insects/arthropods in criminal investigation.
FORENSIC ENTOMOLOGY
-Right from the early stages insects are attracted to the decomposing body and may lay eggs in it.
FORENSIC ENTOMOLOGY
-By studying the insect population and the developing larval stages, forensic scientists can estimate the postmortem index, any change in position of the corpse as well as the cause of death.
FORENSIC ENTOMOLOGY
– This refers to an analytical technique that measures the concentrations of elements.
ATOMIC ABSORPTION SPECTROMETRY (AAS)
-The technique makes use of the wavelengths of light specifically absorbed by an element.
ATOMIC ABSORPTION SPECTROMETRY (AAS)
is so sensitive that it can measure down to parts per billion of a gram (µg dm – 3) in a sample.
ATOMIC ABSORPTION SPECTROMETRY (AAS)
CHARACTERISTICS OF TOOLS AND TECHNIQUES USED
a. SENSITIVITY
b. SPECIFICITY
c. RAPIDITY
–consider the physical factor
SENSITIVITY
– Every object, natural or man – made has an individuality which is not duplicated in any other object.
LAW OF INDIVIDUALITY
–time factor or oras
– gaano kabilis?
RAPIDITY
PRINCIPLE USED IN FORENSIC CHEMISTRY
a. LAW OF INDIVIDUALITY
b. LAW OF PROGRESSIVE CHANGE
c. PRINCIPLE OF COMPARISON
d. PRINCIPLE OF ANALYSIS
e. LAW OF PROBABILITY
f. WITNESS
– Any physical location in which a crime has occurred or is suspected of having occurred.
CRIME SCENE
– All identifications, definite or indefinite, are made consciously or unconsciously on the basis of probability.
LAW OF PROBABILITY
– The analysis can be no better than the sample analyzed.
PRINCIPLE OF ANALYSIS
– Everything changes with the passage of time.
LAW OF PROGRESSIVE CHANGE
– Only “likes” can be compared.
PRINCIPLE OF COMPARISON
–scene where pieces of evidence are located
CRIME SCENE
TYPE OF CRIME SCENES
- PRIMARY CRIME SCENE
- SECONDARY CRIME SCENE
– The original location of the crime or accident.
–all physical evidence are here
PRIMARY CRIME SCENE
– An alternated location, such as where additional evidence may be found.
–additional physical evidence can be located here
SECONDARY CRIME SCENE
– Second person associated with committing a crime.
ACCOMPLICE
–person at the law enforcement stage
SUSPECT
– Person thought to be capable of committing a crime.
SUSPECT
– Statement of where a suspect was at the time of a crime.
ALIBI
– Is a means, sanctioned by law, of ascertaining in a judicial proceeding the truth respecting a matter of fact.
EVIDENCE
KINDS OF EVIDENCE
- TESTIMONIAL EVIDENCE
- PHYSICAL EVIDENCE
- TRACE EVIDENCE
TYPES OF TESTIMONIAL EVIDENCE
ORDINARY WITNESS
EXPERT WITNESS
– Would be any witnessed accounts of an incident or crime.
–placed in writing
TESTIMONIAL EVIDENCE
– Any material items that would be present on the crime scene or the victims.
PHYSICAL EVIDENCE
-Presented in a crime investigation to prove or disprove the facts of the issue.
PHYSICAL EVIDENCE
– Refers evidence that is found at a crime scene in small but measurable amounts.
TRACE EVIDENCE
-E.g. DNA, Body itself, Weapon used, Pieces of carpet, Blood and other body fluids, Fingerprints or casts of footprints or tire prints and etc.
PHYSICAL EVIDENCE
–can tell the location of the perpetrator in CDI
TRACE EVIDENCE
– The means sanctioned by law, of ascertaining in a judicial preceding the truth respecting a matter of wherein scientific knowledge is necessary.
SCIENTIFIC EVIDENCE
is a fact – finder, but he must know laws concerning the nature of his activities.
investigator
He should procure evidence in such a way that findings can be admitted in court and remain impregnable to any attack by the opposing counsel.
investigator
– An expert witness may be required to perform certain of this to prove a certain matter of fact.
EXPERIMENTAL EVIDENCE
– Evidence which is addressed to the senses of the court.
REAL OR AUTOPTIC EVIDENCE
FORMS OF SCIENTIFIC EVIDENCE
- REAL OR AUTOPTIC EVIDENCE
- TESTIMONIAL EVIDENCE
- EXPERIMENTAL EVIDENCE
- DOCUMENTARY EVIDENCE
– Comes from people
e.g. Testimony of an expert witness in court
TESTIMONIAL EVIDENCE
–no need to perform in court, by merely the presence of JUDGE
EXPERIMENTAL EVIDENCE
– Any written evidence presented by an expert in court.
DOCUMENTARY EVIDENCE
- anything that gives or remove your authority
DOCUMENT
BASIC FORMS OF EVIDENCE
- DIRECT EVIDENCE
- CIRCUMSTANTIAL EVIDENCE
- HEARSAY EVIDENCE
– That which the senses perceive.
DIRECT EVIDENCE
-Any fact to which a witness testifies based on what he saw, heard, smelled, touched or tasted.
DIRECT EVIDENCE
–evidence that can stand on its own, no need to support to prove its facts
DIRECT EVIDENCE
– A kind of evidence which seeks to establish a conclusion by inferences from proved facts.
CIRCUMSTANTIAL EVIDENCE
-An evidence which establishes a fact or circumstance from which the court may infer another fact at issue.
CIRCUMSTANTIAL EVIDENCE
–evidence that it will not be legally binding without the support
CIRCUMSTANTIAL EVIDENCE
– A statement made by a witness on the authority of another and not from his own personal knowledge or observation.
HEARSAY EVIDENCE
is inadmissible except with certain well – defined exceptions.
HEARSAY EVIDENCE
-Some of the common exceptions to the rules of exclusion generally applicable to this evidence are declaration against interest, dying declarations, res gestae, reputation, public records and statement made at a prior time.
HEARSAY EVIDENCE
– One who testifies in court and has personal knowledge or experience of something.
WITNESS
-A person, other that the suspect who is requested to give information concerning an incident or person.
WITNESS
-He may be a victim, a complainant, an accuser, a source of information and an observer of an occurrence.
WITNESS
-A ____ in court may be an ordinary or expert witness.
WITNESS
TYPES OF WITNESSES
- ORDINARY WITNESS
- EXPERT WITNESS
– It refers to one who states facts and may not express his opinions or conclusion.
ORDINARY WITNESS
-The rules of court require that the person must have the following qualifications:
- He must have the organ and power to perceive.
- The perception gathered by his organ of sense can be imparted to others.
- He does not fall in any of the exception provided for by the law, Sec. 26, Rules 123, Rules of Court.
ORDINARY WITNESS
– 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
– First step in processing a crime scene is to determine what allegedly happened, what crime took place, and how was the crime committed.
INTERVIEW
-He is a person skilled in some art, trade or science to the extent that he possesses information not within the common knowledge of man.
EXPERT WITNESS
–ang makakapagsabi kung expert witness siya ay ang
JUDGE or the COURT
In weighing the testimony of an expert, all the circumstances of the case must be taken into consideration, among them:
- The degree of learning of the witness;
- The basis and logic of the conclusion; and
- The other proof of case.
– Second step in the investigating a crime scene.
Examine
-May not be factual information.
INTERVIEW
how many hours can you extract an information during the interview?
1 to 2 hours
-It gives the investigators a place to start.
INTERVIEW
-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
– Third step in the protocol.
Photograph
-It involves creating a pictorial record of the scene and record items of possible evidence.
Photograph
–its purpose is to “preserve the pieces of evidence”
–we can connect the evidence with this
Photograph
– Fourth step in the protocol.
Sketch
-Drawing a rough sketch.
Sketch
-Demonstrate the layout of the crime scene or to identify the exact position of the deceased victim or evidence within the crime scene.
Sketch
–suffice or back up the evidence
–it is additional or another way to preserve evidence
–it is for crime scene reconstruction
Sketch
– Last step in the protocol.
Process
-Crime scene technician will ___ the crime scene for evidence, both physical and testimonial evidence.
Process
-Crime scene technicians to identify, evaluate and collect physical evidence from the crime scene for further analysis by a crime laboratory.
Process
of expert testimony whether courts are, or are not bound by the testimony of an expert, depends upon the nature of the subject of inquiry.
Probative value
When, however, the subject of ______ is of such a nature that a layman can have no knowledge thereof, as for example, the determination of parentage by blood test, the court must be dependent on expert evidence.
inquiry
The average _______ is in constant contact with various investigative and law enforcement agencies and he should learn to speak their language.
investigator
may be defined as the means sanctioned by law, of ascertaining in a judicial proceeding the truth respecting a matter of fact wherein scientific knowledge is necessary.
Scientific evidence
it is based on or conforming the principles and techniques of science.
Evidence
- Analysis of material leading to legal proceedings
Forensic Chemistry
- Analysis of material leading to legal proceedings
Forensic Chemistry
-Not only purely chemical questions but aspects of Forensic Science
Forensic Chemistry
-Not only purely chemical questions but aspects of Forensic Science
Forensic Chemistry
It is probably the most damaging evidence which can break down the hardened criminal.
Physical evidence
It is probably the most damaging evidence which can break down the hardened criminal.
Physical evidence
