CSI FINAL EXAM

Goals of a crime scene investigator

1. do not rush the investigation

2. avoid mistakes

3. keep an open mind

4. maintain objectivity

What are crime scene investigators working for

the truth

Duties of crime scene investigator

document the scene, identify the evidence, properly process and collect the evidence, properly process and submit the evidence, prepare written reports and additional supporting materials

Highest priority of the investigators

safety

Who is considered on the CSI team

detectives, analysts, prosecutors, defense attorneys, reconstruction investigators

Definition of a search

an action by the government that intrudes on a person’s reasonable right to privacy (buildings, residences, structures, vehicles)

Questions to ask when doing a search

1. Do they have a reasonable expectation of privacy?

2. Does the person have the standing to grant permission for the search?

Requirements of scope of search

1. May not exceed the consent given

2. May not exceed the legal authority provided (warrant or court order)

Who has jurisdiction over a dead body

coroner or medical examiner

Constitutional amendment that deals most with an individuals right to an expectation of privacy

4th amendment - protects a person against unreasonable search and seizure

Key elements of a consent to search

1. it was voluntary

2. there was no trickery

3. no promises were made

4. did they have standing

Emergency doctrine

someone needs medical assistance, only with the sanctity of life, the need for the protection of life or risk of harm must be the primary motive (example a missing child, you could be looking for child and find a meth lab)

Exigent circumstance

a warrantless search may be found to be reasonable in the face of exigent circumstance such as threat to human life or imminent destruction of evidence, probable cause must exist

Hot Pursuit Rule

may enter a house when in pursuit

What does a search warrant include

probable cause, facts to show probable cause, description of premise to be searched, address or physical description of the area, what we are looking for

Affidavit

for the judge to understand who is requesting the warrants and what is to be searched and why

A sworn statement from a peace officer. It is not a warrant until signed by judge

Probable cause

the government has probable cause when the facts and circumstances within their knowledge and of which they have reasonably trustworthy information that would lead a prudent person to believe an offense was or is being committed

Pyramid of belief

reasonable suspicion, probable cause, preponderance (civil case), clear and convincing, beyond a reasonable doubt (criminal case)

Plain View Doctrine

officer must have the legal right to be present, use of ordinary sense, immediately recognizable as illegal, flashlights are allowed but other tech isn’t (thermal radiation), any movement or manipulation required to ascertain whether an item is evidence/contraband constitutes a search

Open Fields Search

1. includes pastures, open waters, woods, and other areas

2. areas outside curtilage, much less expectation of privacy in open fields

Curtilage

areas around a person’s home, can include some or all outbuildings such as garage or banrs more expectation of privacy with curtilage

Abandoned Property Search

1. There are no 4th amendment protections for abandoned property

2. You lose expectation of privacy because you left it

3. Trash, nobody goes back for it

Potential dangers at crime scene

suspect still at the scene, biohazards, elemental hazards, other people, structural hazards

Carroll Doctrine

A vehicle can be searched without a warrant if there was probable cause to believe that evidence is present in the vehicle, coupled with exigent circumstances to believe that the vehicle could be removed from the area before a warrant could be obtained

Three key elements in documentation process

1. photography

2. sketch

3. field notes

What information should be noted first in field notes

Why are you there? What called you to be there?

Case law relating to release to crime scene photos depicting deceased photos

Kobe and Gianna Bryant Act - 2023

1. law directly applies to those who respond to crime scenes

2. offense for unauthorized publication of photos

3. images of deceased people or human remains

4. Texas criminal penalty is state jail felony

Camera settings

1. stop - refers to all adjustments

2. exposure - commonly refers to the proper amount of light

3. aperture - iris of the camera

4. depth of field - the area of sharp focus

5. shutter speed - how long light enter the image

6. ISO - how sensitive the camera is to light

Flash photography

1. direct flash

2. off camera flash

3. bounce flash

4. fill flash

5. focused flash

6. use of diffuser

7. oblique lighting

Case Law on photography

photographs must be a true, fair, and accurate depiction of the scene

they cannot misrepresent what is being photographed

must be relevant or material to the point of the issue

do not appeal to the emotions of the jury

What can be used to secure a crime scene

officers, tape, barriers

Exclusionary rule

evidence obtained illegally will NOT be admitted into the court

Fruit of the poisonous tree doctrine

any additional information obtained from an illegal search will also be admissible in court

Good faith exception

evidence obtained by officers acting objectively and in good faith may still be admissible if a warrant is proven to be invalid

Inclement Weather

such as rain or wind can create a situation of exigent circumstances, where there is no time to obtain a warrant or consent

What to include in vehicle processing

License plate, VIN, or tags and vehicle condition

Begin inside and finish outside

Most commonly used type of camera flash in crime scene investigations

Direct flash

National Databases

1. AFIS (integrated automated fingerprint identification system): fingerprints, majority of fingerprints come from arrests

2. CODIS (combined DNA index system): DNA

3. NIBIN (National integrated ballistic information network): ballistics, can identify weapons, criminals, patterns of crimes

Circle or Spiral Search

• Begin at the edge or center of the circle

• The circle expands and becomes larger or smaller

• Can be used in underwater searches

• WARNING: no definite points of reference, may result in missing evidence, not recommended for cluttered areas

Lane or Strip Search

• Frequently used by law enforcement

• Walk in a line then return a few feet over

• Dependent upon natural and artificial lighting

• Helpful in parking lots

Grid Search

• Similar to a lane search

• Covers areas more than once

• Typically on search is conducted in a 90-degree angle from the first search

• More thorough than a single lane or strip search

Line Search

• Similar to strip or lane search

• Searchers go in one direction

• Useful for large areas

• Useful when large number of searchers are available

• You should only use law enforcement, suspect could inject themselves into the search

• Good for missing kids

Zone Search

• Needed when scenes are very large and need to be broken into manageable pieces

• Areas are marked in a way which identifies them (wood stakes, strings, and letters/numbers)

Point to Point Search

• Point of interest to point of interest

• Common in searches looking for an item

• Documentation goes from one piece of evidence to the next

• Evidence can be overlooked or lost

• Allow investigators to keep track of evidence collected

• Does NOT detail a sequence

Search pattern impacted by natural and artificial lighting

Lane or strip search

Search Patterns recommended for large areas

Zone (can be broken in manageable pieces)

Line (bunch of people helping)

Considerations when selecting a search pattern

Safety, terrain, priorities (information can redirect searches, what will be damaged?, situations can change, circumstances change), weather

Levels crime scenes should be examined

ground level, eye level, and above

How weather can work for or against CSI

• Freezing: can preserve the evidence perfectly

• Rain: can wash away evidence but also introduce a need to have to search

• Heat: kills DNA and other evidence

What presumptive testing is and is not

• a presumptive will provide one of two results

  • the sample is definitely not a certain substance

  • the sample is probably the substance

• Presumptive tests are not specific tests

  • sensitivity: describes some test are capable of reacting when there is very dilute chemical

  • specificity: refers to tests that react with a specific substance

Cautions of Hemastix

• may be vulnerable in extreme cold

• cannot distinguish between human and animal blood

• may be sensitive to direct sunlight

• false positives/negatives

Substances that enhance the ability to see blood stains which may have been cleaned

• Luminol: precursor to BlueStar

• BlueStar: brighter more visible reaction, more stable mixture, less reapplication needed, does not damage DNA

Fingerprint development and characteristics

• Ways to alter fingerprints have proved to be ineffective

• it is perfectly fine to find the same item or a similar item and try different techniques

Benefit fingerprints can provide in CSI

• fingerprints are yours before you’re even born

• proving the presence of someone at the scene of the crime

• proving innocence of a suspect

• identifies people

Classification patterns of fingerprints

1. arches - 5%

2. loops - 65%

3. whorls - 30%

Latent vs patent vs plastic fingerprints

• Latent: an impression of the friction ridges of all or any part of the finger, what is left behind when a person touches an item, invisible to the naked eye

• Patent: visible, requires no additional processing to be visible

• Plastic: occurs when the surface touched is soft and conforms to the ridge pattern

What is the perfect fingerprint powder

• THERE IS NONE

  • aluminium flake powder

  • granular powder

  • magnetic powder

Zephyr vs artistic brush

Zephyr: longer bristles and cover more area

Artistic: stronger and shorter bristles

What needs to be included on fingerprint card

• Case number

• Type of crime

• Who took it

• Diagram

• Location of collection

• Item description

Best surfaces for fingerprint collection

• Smooth/non-porous

• Rigid/stable

• Clean

Preferred methods of collection

• paper bags

  • biological evidence

• plastic bag

  • risk of mold

  • if there is no biological agent

Guidelines for swabbing

• use sterile swabs

• use distilled or sterile water

• always wear gloves

• applied heat or commercial dryers can contaminant and destroy DNA

Consumption orders

• everything you have will be gone after, single time only

• deal with very small samples or when only a single swab was collected

• may be restricted or allowed via jurisdiction

Liquid Samples

• place samples in tightly sealed containers

• do not fill containers more than ½ the way

• store containers in an upright position

What is evidence

all the means by which any alleged matter of face whose truth is investigated at a judicial trial is established or disproved

Testimonial Evidence

• most common type of evidence heard by juror

• witness statements

• subjective judgement of the person testifying

Demonstrative Evidence

• less frequently used

• provides demonstration to jury

• allows the presentation of theories of what occurred

• must be supported by physical evidence

• 3D imagery

Circumstantial Evidence

• there is no clear evidence

Physical Evidence

• juries put more stock and place more value on physical evidence

• may prove a crime has been committed

• may place a suspect at the scene

• may place a victim at the scene

• may place a suspect in direct contact with a victim

• physical evidence is neutral and objective

Most common evidence

Testimonial

Which evidence allows for theories

Demonstrative

Where is computer imagery growing in importance

officer involved shooting

Exchange Principle

Every contact by a suspect leaves behind a trace

Bank Security Dyes

money senses it is leaving the bank and then it explodes when far away, the chemicals are unique to each bank to identify the banks, intended to stain the money permanently, not as used anymore because people know it exists, now we have trackers in the bills

Chemicals of unknown origin

first concern is safety, meth lab, wear protective gear, could have to figure out what chemical someone consumed such as a child, roofies

Explosives

we do NOT process explosives, ATF/FBI/local bomb squads’ job

What type of evidence can be identified by their unique comp

cigarettes, tobacco, dye packs, explosives, chemicals

Glass transference

floor, suspect’s clothes

could determine the way the window breaks

blood on window climbing in

Three types of glass

1. Laminated: windshields, has a plastic layer, it breaks but holds together

2. Tempered: has been heated, it breaks a certain way, breaks into small pieces

3. Plate: breaks into various size pieces

Hair DNA

The shaft contains mitochondrial DNA

The root contains nuclear DNA

Nuclear vs Mitochondrial DNA

Mitochondrial: less discriminating, inherited from maternal parent, does not provide complete identification, mothers and daughters can share

Nuclear: more discriminating, may provide positive identification

Trace evidence

• most commonly requested in sexual assaults

• generally evidence that is very small and considered the most fragile

• often overlooked

• tiny fragments of physical evidence like hair, fibers, glass, etc…

Categories of Firearms

• Handguns: designed to be held and fired with one hand

• Long Guns: designed to be fired with both hands

  • single shot, revolver, automatic, semi automatic, shotgun

Safety concerns when handling firearms

• inherent dangers exist due to the nature of firearms

• all firearms should be considered loaded

• each CSI investigator should inspect the firearm personally

• firearms should NEVER be pointed at someone

Fracturing

• common from drill bits

• may occur due to incomplete saw cuts

• generally not obtainable from a circular saw

• generally not obtainable from a completely cut object

• generally not obtainable when hole is completely drilled

Impressions

• caused by the indentation or depression of one object upon another

• hammer, mallets

• common with safes

Pinching

• pilers and tweezers

• caused when an object is squeezed between two points

• common on locks

Scraping

• caused when a sharp or angular object is drawn across another

• nails, keys, screwdrivers

• common is keying someone’s car

Shearing

• caused by offsetting cutting blades

• scissors, tin snips, wire cutters, bolt cutters

• common with wire fencing

Slicing

• caused by the movement of a sharp object through another

• knives, swords

Single Shot

• ammunition loaded one at time

  • lever action rifles

  • bolt action rifles

  • break open

  • derringer

• reload after each shot

Revolvers

• rotating cylinder

• each cylinder holds one cartridge

• cylinder rotates with the trigger pull

• 4 to 24 rounds of ammunition

  • 6 is most common

• each cylinder holds one cartridge

• holds cartridge after firing

• shell casing may not be at the scene

Semiauto

• one round fires with each trigger pull

• referred to as “self loading”

• energy from one fired round loads the next round

Automatic

• fires multiple shots with a single trigger pull

• cartridges are held in a magazine

• may be handgun or long gun

• includes: assault rifles, machine gun, submachine gun, AR15

Shotgun

• barrels are smooth, not rifled

• bullet spreads out to increase chances of hitting something

• closer the shooter is the more condensed the bullet patterns

• farther away, pattern spreads out

• pump action

• single or double barreled

  • side by side

  • over/end

NIBIN Hit

• must be checked by a firearm examiner

• more common to get a hit compared to DNA hit or fingerprint

Magazine

• part of semiauto and automatic firearms

• holds extra cartridges

• not a clip

• cartridges are fed into the firearm

Ammunition

• shot gun ammunition = shotshell or slug

• rimfire = primer is loaded in the rim

• centerfire = primer loaded at the center of cartridge

• ball, semi-jacket, full metal jacket, hollow point

Nomenclature

• can tell you which way the gun was facing, who was holding it, were people fighting over it, hand dominance

Gunshot Residue

• gunpowder burns (not explode)

• deposited on hands, clothes, face, arms

• samples are commonly on hands and face

• look for stippling: burning on skin of gunpowder