CHE 113 Exam 1 Study Guide
This exam covers topics in class from the Chapter 1 – Chapter 5. There is a large amount of information to know, so I would focus on what he highlights in class. This study guide mentions everything he spoke about from the first lecture to the one covering DNA.
Chapter 1 – Forensic Science
Forensic Science History!!
∙ It began in the late 1700s
∙ Real application of the scientific method didn’t start until the 1900s
∙ Alphonse Bertillon
o Late 1800s
o ID repeat offenders
∙ Alexandre Lacassagne Don't forget about the age old question of How does the central nervous system develop?
o Criminal Anthropology
∙ Edmond Locard
o Application of scientific techniques
o First to set up a forensics lab
Locard’s exchange Principle (Edward Locard)
The most basic concept of Forensic Science:
∙ A criminal in contact with something, a cross transfer occurs o EX: dust, fingerprints, chemical residues.
Principle of Individuality
∙ While 2 objects appear as the same, those same objects are never identical. Something sets them apart
o Ex: identical twins are not really identical
Example of the Multidisciplinary approach to Forensic Science ∙ Salem Witch Trials – Bettey Parris in the 1690s became ill o Resulted in dancing and yelling continuously We also discuss several other topics like What is Inquisitor?
∙ Doctors weren’t really respected
∙ King Henry VIII merged the lowlife doctors with the barbers to make the Great Company of Barbers and Surgeons
∙ The barber shop image
o Red – blood
o White – bandages (spirally bloody bandages)
o Blue – tattoo art?
Internal Illness: human body incorporated for different “humours”:
∙ Hot (sanguine: blood)
∙ Cold (choleric: yellow bile)
∙ Dry (Choleric: yellow bile)
∙ Wet (melancholy, black cile )
∙ Illness was caused by an imbalance in the humors External Injury:
∙ The answer is amputation!!
∙ Most died of blood loss, shock or infection If you want to learn more check out what is rubeola virus?
Nothing was working so they assumed that the illness came from the supernatural word – Salem witch trials (June through September of 1692)
∙ 19 men and women convicted of witchcraft were hung on Gallows hill near Salem Village
∙ An 80 yr. old man was pressed to death under heavy stones ∙ Hundreds accused of witchcraft
∙ Dozen put in jail w/o trials
∙ Late 1692, everything ended
In the Salem witch trials
∙ Checked to see if you had moles and such
∙ If not, connected the dots on your freckles and everyone had freckles
the forensic investigation started with Art History – Hieronymus Bosch
∙ Telling stories embedded in his paintings
St. Anthony’s Sacred Fire: Ignis Sacer:
∙ A chemical used to get into your body that makes you feel like you’re extremities is on fire.
It’s called ergotism
∙ Gangrenous Ergotism – nausea, pains I the limb bodily extremities turn black , dry and become mummified, infected limbs spontaneously break off at the joints
∙ Hallucinogenic (Convulsive) Ergotism:
o Flu and fever
o Nervousness, physical mental excitement, insomnia and disorientation
o Vivid hallucinations
o The strange happy dancing - Salem
Made from what could have been fungus – rye grain If you want to learn more check out What are the seven sins of memory?
∙ Has the chemical Ergotamine Tartrate
∙ You put in in bread and the chemical was LSD – which made the town all crazy – forensic toxicology
∙ Ergot fungus – fixed version that could cure migraines?
∙ What is truth
o That which is true in accordance with fact
o Truth is very subjective
∙ What is justice
o The state or characteristic of being just or fair
∙ In court you try to determine guilt vs. not guilty, not guilty vs. innocent If you want to learn more check out What the benefits of being an informed user?
o In court you’re guilty if your get proof “beyond a
To have scientific evidence be admissible in court you look at ∙ “Trilogy” of court cases
∙ form and test hypothesis ->
o Observations and Experiments
∙ Patterns and trends We also discuss several other topics like What is a coaching code of ethics?
Scientific Evidence in Court
∙ Why do we want scientific evidence in court
o Forensic evidence is aimed at informing the court where it lacks expertise
o Assist in determining fact
∙ What is admissible evidence?
o Real Science vs. Pseudo (Quack) Science
o Established how to determine the difference through 4 primary cases (Frye, Daubert, Joiner, and Kuhmo) –
KNOW THEY NAMES don’t need to know the date
∙ Homicide of Dr. Brown during robbery
∙ Later Frye captured and confessed.
o There was a lot of evidence against him
∙ Strong Prosecution Case (1923)
∙ Defense introduced the polygraph and it seemed like they couldn’t tell that the guy was lying so the polygraph got threw out the case
∙ Take Home: They said they would admit evidence if there was general acceptance through experts in that particular field o Through: Books, papers, prior judicial decisions, length of existence of technique
∙ Problems with Frye:
o Inflexible and slow for new developments or extensions of existing technique and methods
Requires complete agreement in the scientific world so that doesn’t happen very often.
Daubert Case – Progression
∙ Drug called Bendectin prescribed for nausea and EVP ( excessive Vomiting in Pregnancy)
o People were saying that they caused Limb deformities o They was clinical evidence against that claim
o Got experts to say that they CAN cause birth defects in animals if given in large quantities
o Court determined that the daubert evidence did not meet the general acceptance
∙ Alternative standard relative to Frye: Takeaway: o More flexible:
A witness qualified as an expert by knowledge skill, experience, training or education, may
It’s based on sufficient fact or data
It is a product of reliable principles and
The principles are applied reliably to the
facts of the case.
∙ ACTUAL TAKEAWAY
o Assigns trial judge the gatekeeper responsibilities in determining the admissibility and reliability of scientific evidence
General Electric vs. Joiner Case
∙ Case where GE was accused of a drug that was cancerous (PCB)
∙ So conclusions come from data, and if an expert has data and also has an opinion that’s not related to the data, the jury can disagree with that sentiment
Kumho Tire Case
∙ People felt like the tires were defective and therefore caused injury..
∙ Testimony was essentially unreliable
o “make certain than an expert employs the same leveled of intellectual rigor that characterizes the practice of an expert in the relevant field”
Melendez-Diaz vs. Mass
∙ Lil confused on this one.
Functions of the Forensic Scientist
∙ Examine evidence
∙ Perform the appropriate analysis or measurement ∙ Render a conclusion based on evidence
∙ Testify in court
**at home reading in the lectures
Uncertainty in Measurement
∙ Precision – how closely individual measurements agree ∙ Accuracy – how closely the measurements agree with the true value
What is Evidence?
∙ Evidence – info that can influence beliefs of an observer about a specific legal question
∙ Must be more probative (why) than prejudicial (accusatory)
Role of Forensic Science
∙ Science is a process that permits one to test hypotheses ∙ Science cant prove anything more complex than a simple fact ∙ Science operates by falsifying hypotheses not proving them. To Test whether xyz NOT establish xyz
Chapter 2 – Physical Evidence What is physical evidence?
Any material object that plays some actual role that gives rise to the litigation, introduced in a trial, intended to prove a fact in issue based on the object’s demonstrable physical characteristics. ∙ Ex: blood, semen, silica, documents, drugs, fingerprints
Physical Evidence: Analysis
∙ Identification - What is it? Determination of physical or chemical identity of a substance with a near absolute certainty as existing analytical techniques will permit o EX: drug analysis, species determination
o Methods : gas chromatography/ mass spectrometry ∙ Comparison – Very important. Comparing a sample that we collected and compare it with a standard or exemplar to determine if they have a common origin.
o Is this fingerprint the same as the one in this crime scene.
Comparison: Physical Evidence
∙ One to many Matching
o Collected one and then trying to see like everything you have and see if it matches up on the data base
∙ One to One Matching
o Comparing crime scene fingerprint with the one you have .
o Ex: the iPhone compares the incoming fingerprint to the fingerprint you put in, not everyone’s fingerprint on
Physical Evidence: Types
∙ Class (group) Characteristics – Properties of evidence that can only be associated with a general group and not with a common source
o Ex: blood type, paint or dye lot
∙ Individual Characteristics – properties of evidence that can connect a sample and standard to a common source (with high probability)
o Ex: fingerprints, unusual wear patterns, tool marks, bullets, knives, shattered headlight
Advantages of Class Physical Evidence
∙ Multiple types of class of evidence may lead to an extremely high chance that they originated from the same source. ∙ To find the probability of a person having x,y and z you multiply the general probability of x y and z by eachother.
Physical Evidence – Lindberg Kidnapping Case
∙ Child (20 month old son) put down for bed was kidnapped. Ransom note on window sill
∙ Lots of evidence was found…. Mud, footprints
∙ The child was found dead in the woods – blunt force trama ∙ My son made a whole homemade ladder that they used to abduct the kid
o There were floor boards missing in the attic
o The boards age rings matched up . the chance of that happening was od small
∙ The bullet hit the president and the governor so it makes sense at their entry points for it to be one gun that was shot that went through both of them
∙ Locards Exchange Principle – Whenever two objects come together they must affect each other in some way. Something is likely to be exchanged between them.
Principle of Individuality – Even though two objects may be indistinguishable, they can never be identical
**4th Amendment defends our privacy and no warrants will be used unless there is probable cause
∙ we have the right against “unreasonable searches and seizures”
o What is unreasonable?
Allowances for warrantless searches
∙ Search of person or property within immediate control of person in a lawful arrest.
o The backpack on the guy you arrest
∙ An emergency
∙ Plain View
∙ Roadside Checkpoints (immigration and DUI)
∙ Airport, boarder searches
∙ The need to prevent the immediate destruction of evidence ∙ Stop and frisk -> suspect criminal activity
∙ Inventory searches. (ships/ cars of suspicious things) ∙ National Security (USA Patriot Act)
∙ Administrative Services (safety, fire)
∙ Only applies to government officials -> NOT private security officers -> mall cops
∙ Illegal search can lead to elimination of evidence or overturning conviction (but may be used in the sentencing phase
∙ Under most circumstances, a warrant is needed
∙ But, only when there is a “legitimate expectation of privacy” phone booth vs. public bathroom -> 4th Amendment kicks in o If you put the camera in a stall you need a warrant but by the sinks you don’t
o Phone booth : need the warrant if you put a
microphone and will hear the audio, but not for a
camera because everyone can see you in there
∙ supreme court generally does not want to put under restrictions on the daily work of law enforcement
∙ Ownership to give consent?
o Dorm rooms, home bedroom, etc.?
o You can only consent to share spaces.
o As long as the kid doesn’t pay rent the mother can agree to searching
∙ Mistaken Search, “Good Faith”
o Mistaken got other people w/drugs when looking for the guy w/gun -> admissible evidence
∙ Searches in malls, stores, Disney World, backpacks, schools -> don’t follow this?
∙ Car GPS data, black box or police affixed gps
o Need a warrant unless the cars on fire
o If they want to track a car -> need a warrant
∙ Pat down frisks-> find drugs can be legal if they see something
∙ Good Faith
Plain View Doctrine – don’t need a warrant to seize things that are in plain view. From a place the officer has a right to be (sidewalk, roadside..)
Exclusionary Rule – If you got evidence illegally -> It’s inadmissible
Fruit of the Poisonous Tree Doctrine – If you get evidence illegally, anything else that comes from that is also illegal
Illegal evidence can be used:
∙ When sentencing
∙ Admissible in civil cases and deportation cases
∙ To impeach/discredit a witness
Collection of Evidence – Legal Precedent –Miney vs. Arizona ∙ Drug bust went wrong when undercover police got killed ∙ Police spent 4 days searching and seizing
∙ Mincey was arrested and convicted
∙ Inadmissible evidence because they spent 4 days, the “emergency” lasted a shorter time
Michigan vs. Tyler
∙ Building destroyed by fire was put out early in AM ∙ Building left unsecured and they in on days (4, 7, and 25) to get evidence
∙ Inadmissible evidence – uncontrolled scene, they waited too long and they cant say what or what not had been tempered with.
∙ Must be recognized at crime scenes
o What relates to the crime and what doesn’t
∙ Must be properly collected, preserved and controlled ∙ Only aids in investigation
Steps take at a Crime Scene
∙ Secure and Isolate the scene
∙ Render medical help and arrest suspects (if need) ∙ Preserve and protect evidence (isolate area)
o Exclude unauthorized personnel
o Designate Officer in Charge (with authority)
o Establish boundaries
o Document site
∙ Collection of Evidence
Crime Scene Searches – Lockerbie Bombing
∙ 35 SU students killed by terrorist bomb in Dec 15. (Pan Am Flight 103)
∙ Crime scene spread over 845 sq. miles of Scotland ∙ Discovery: Crime Scene spread over 845 sq. miles of Scotland and came out with a little piece of evidence that helped them solve the case
Chain of Custody : documentation of transfer of evidence ∙ It's a piece of paper that everyone has to write on if you’ve touched the evidence.
Chapter 3 –Science vs.
Pseudoscience – saying dihydrogen monoxide kills!!-> it’s H20 Science – systematic knowledge gained through observational experimentation
Pseudoscience – a discipline or approach that pretends to be science
∙ Damages reputation of scientific work
Audi 500 Case
∙ Claims that drivers reported acceleration even when the brakes were applied
∙ “60 minutes” story on claims led to increased claims with many lawsuits
∙ Demo: full acceleration with foot on the brake prevented car from moving
o Court finding: for plaintiffs (against Audi)
Science vs. Pseudoscience
∙ Pseudoscience relies on trust while science relies on experimental validation and evidence.
o Exaggerated claims
o Try to fill voids of scientific understanding and when they fail they make science look bad
o Based on hearsay
Testing ideas: Statistics
Statistics: given the little information what can I say about the population
Probability: given the population, what can you say about the individual
∙ Mean, median, mode
∙ Standard deviation :indicates the breadth and the distribution of data in a set
o If small, then steep hill if large, then spread out curve ∙ Error bars: a convenient way to show directly on the plot
Of this and this happening = this times this
Chapter 4- Microscopy
We use microscopy to extend our human senses: sight, smell, touch….
How our Eyes work
∙ Pupil, lens (that acts as a magnifier)
∙ In the back they’re specialized cells (retina) causes those cells to send electrical impulses from the light
∙ We have to replace the light with something smaller so we magnify the image.
Compound Light Microscope
∙ Most common: compound light microscope
o Has two lenses that the light can pass through
Dark field Microscopy
∙ Shows a light silhouette of an organism against a dark background.
∙ The light reaches the angle because the light bends so the image is very bright
∙ Pretty cool
∙ Block the normal straight line light, and only light that aluminates the sample reaches my eye.
∙ 2 microscope that you use to bring an image together – there are two lenses, one for each eye
∙ split image comparison of banknotes: on the left original, on the right -> forgery
∙ this microscope splits a beam of light into 2 types of light, and brings them together to form an image of the specimen ∙ “in phase” – image is brighter
∙ “Out of phase” – image is darker
∙ Light confined to single plate that is polarized
∙ Reduces glare by transmitting light in a vertical plane only. o you have to twist the sample to be able to get the like through so that you can see
∙ Specimens are stained with fluorescent chemical so it glows under the UV light
∙ Appear as dark background and its glows
∙ Also called the dissecting microscope
∙ The light goes to the sample and bouncing everywhere till it gets to your eye
∙ A beam of electrons are shot through the specimen ∙
Chemicals that are added that stick to certain structures that allow me to see them easier.
Chapter 5 - DNA
Forensic DNA: Two Tales
Had the attackers DNA patterns from each case and went to go compare them to 500 samples but they didn’t even match ∙ Colin Pitchfork Case (1986)
o He confessed to his friends, they turned him in and they compared his DNA to the sample they had from the
First time dna was used for conviction
∙ WTC Case (2001)
How DNA Works: Nucleic Acids
Nucleic Acids – chemical carriers of generic information (DNA and RNA)
∙ Consist of;
o A phosphoric Acid Molecule (phosphate)
o 5 carbon sugar (ribose)
o Nitrogen base
Information lies here
∙ All linked through condensation reactions to form polymers ∙ Double Helix with Two strands via hydrogen bonds when the bases line up
o G to C
o A to T
DNA in the Cell
DNA strands coils up to form chromosomes ∙ you get DNA from your mom and dad
Human Genome Project
∙ determined out we have 30,000 genes that code for things we need
∙ found humans share 93% of our DNA with worms ∙ only 1.5% of DNA is codes for compounds -they rest is complicated
gene – short portion of DNA that codes for something ∙ happens on the coding sections
∙ 3 base pairs corresponds to 1 amino acid
∙ Builds Proteins
∙ Proteins – enzymes, all functions for life.
∙ The dna strand splits in half and coding strand gets transcribed (matched up)
o Translation: Then it goes to the ribosome where every 3 bases get amino acids that make proteins
DNA Cellular Sources
∙ Located in nucleus
∙ Half mom and half dad
∙ Located in mitochondria
∙ Inherited just from mother
Where is DNA
Cellular Matter – where is DNA everywhere?
Human Identity Testing
∙ Forensic cases – match or eliminate suspect with evidence ∙ Paternity testing – Match or eliminate possible father(s)
African Lemba Lineage
∙ Looking at a marker on the Y chromosome that men have ∙ Found
o 50% of marker founds in Cohanum males were in 10% of all Jews
o they have some kind of relation
∙ Collection of Sample
∙ Separation and Purification of DNA
DNA Fingerprinting “RFLP”
∙ “Restriction fragmentation –“
o Restriction DNA with cut DNA into fragments in different lengths
∙ Some enzymes recognize a set of bases and when they do, they cut the hydrogen bond
o Now you have comparable fragments for DNA
∙ Gel Electro.
o Put the fragments in machines and then they line up based on size
o So its easier comparison
∙ Sequences of DNA that repeat over and over next to eachother
o Intergene region that contain many A,T,C,G repeats ∙ Forensic DNA typing uses tandem repeats
o All humans have many tandem repeats
o Great variation per person – how many and where is different
Somebody could have 4 tandem repeats or 6
tandem repeats for one gene
PCR/STR DNA Typing
∙ Uses shorter, more stable DNA lengths and deals with less of the simple
∙ Works with the tandem repeats
∙ Allows you to copy the repeated section and they if you figure out how long the sequence can be