Adv Crime Scene Processing FINAL

what is the 4th ammendment?

protects people from unreasonable searches and seizures by the gov

what are the requirements for a search warrant?

1. that a crime has occurred

2. particular evidence of that crime is in a particular place

3. evidence is in that particular place now

what are the documents involved in the search warrant process?

affidavit, search warrant itself, return and inventory

what are the exceptions to a search warrant? (5)

consent, exigent circumstances, abandoned property, open fields rule, plain view

what is an affidavit?

a sworn statement of a law enforcement officer setting forth the facts amounting to probable cause.

what is a return and inventory document? (taken within how many days of service?)

the officer must return to the judge and swear that the search was executed and provide an inventory of the items taken. This is usually required within 10 days of service.

what is a search warrant?

the order of the judge commanding police to execute the search and authorizing the seizure of evidence.

what does jurisdiction mean?

the official power to make legal decisions and judgements

in oklahoma, what are examples of state agencies?

highway patrol, OSBI, oklahoma bureau of narcotics

what are examples of federal agencies?

FBI, DEA, Secret Service, Marshal’s Service

what are the 3 federal districts in oklahoma?

WDO: OKC

NDO: Tulsa

EDO: Muskogee

what is the purpose of memorandums of understanding?

to address how they will work various crimes and crime problems. These are written agreements but are not considered contracts.

in oklahoma, who has jurisdiction of the body?

the office of chief medical examiners

what are examples of transient evidence that could be found on a body? how should you recover them?

part 1:

• hairs

• fibers

• GSR

• blood spatter

• DNA

part 2:

• must work with ME to preserve evidence

how should you photograph a body?

start with mid-range pics relating the body to a fixed feature of the scene, a body panorama, close-up of face, birds-eye view, and any identifying features

for photos of a body, for each wound, identifying feature, or bloodstain you should…

take mid-range using joints as fixed points AND take close-ups with a scale

what are the basic mechanisms of injury?

asphyxia, sharp force trauma, blunt force trauma, gunshot trauma

what is asphyxia?

Results when the body is unable to take in oxygen or eliminate carbon dioxide

what is sharp force trauma?

wounds such as a stab, incision, chop, or puncture

what is blunt force trauma?

Occurs as a result of crushing of associated tissue (wounds include abrasions, contusions, lacerations, and fractures)

what are the 4 types of gunshot wounds? describe them:

penetrating (entry only), perforating (entry and exit), grazing (strikes parallel to surface of skin), and tangential (skims across skin’s surface)

what is stippling and when does it happen?

stippling happens when the muzzle of a gun is pressed on the body when it fires; which causes hot particles to cause small burn marks to be present on the skin

what is the difference between lividity and a contusion?

lividity is a post-mortem change, a contusion is a living injury

what is cause of death vs manner of death?

• Cause: mechanism that directly led to death 

• Manner: category of how the death was caused (natural, accident, suicide, homicide, undetermined)

what is post-mortem interval?

PMI is the approximation of time between death and discovery of body 

what are the early and late post-mortem changes? what happens in these stages?

Early changes

• Rigor Mortis: Apparent stiffening of the muscles of the body after death

• Livor Mortis: Settling of the blood in the body due to gravity after blood circulation ends (lividity) 

• Algor Mortis:  Loss of body heat resulting from death; declines until reaches equilibrium with ambient temp

Later changes (decomp)

• Putrefaction: bacteria from gut begin to take over and lyse cells 

• Saponification: Requires moist cold conditions such as burial, plastic bag, or water.

• Mummification: Requires high heat; low humidity; and good ventilation

how is the post-mortem interval related to time of death?

the post-mortem interval helps determine the time of death (Shorter the PMI, narrower the TOD range)

if you find adult insects on a body, how should you preserve them?

in 70% ethyl alcohol (etoh)

if you find immature insects on a body, what should you do with them before you place them in 70% etoh?

fix them in hot water

how should you store insects that you collect from a body?

place in fridge or cooler, DO NOT freeze

why do CSI use ALS?

to aid in the visualization of evidence beyond what is readily apparent to the naked eye. 

what is the difference between reflected light and converted light?

Reflected: bounces light, defines color; white: all colors reflected

Converted: excited electrons release energy appearing as fluorescence

what is photoluminescence?

Fluorescence: Immediate reaction; stops glowing after light is removed 

Phosphorescence: Light released gradually up to several hours 

what type of filter should you use with UV light?

UV or yellow

how do you know what type of barrier filter to use for ALS photography?

Use a complementary filter color to remove the original light (ex: orange filter for wavelengths of blue light).

what is the most common filter and light combo for CSI?

Blue light with orange filter

what is LiDAR?

captures the shape of objects using a line of laser light and analyzing the reflection.

what are the 4 scanner types?

terrestrial, airborne, handheld, mobile

What is the resolution of a scan? what does a high resolution do?

Density of the points

High resolution creates “a more realistic depiction of the scene”

what should you consider during scanner placement?

where areas may overlap to create a higher resolution

for substance testing, what is sensitivity vs specificity?

Sensitivity: Ability of test to detect substances that are diluted

Specificity: Ability of test to detect a particular substance without false positives

when do CSI conduct a presumptive test?

 to indicate the possible presence of biological evidence

what is a confirmatory test?

Confirms the identity of a substance

what does hemastix test for and what color change should you look for?

blood and urine; green/blue color change

what is Phenolphthalein and what color change should you look for?

like hemastix but is less sensitive and more specific, color change is pink

what can cause false positives during presumptive tests?

• Oxidizing agents (household cleaners, nail polish, rust) 

• Plant Peroxidases (tomato, potato, horseradish) 

what is chemiluminescence? what does its high sensitivity cause?

Luminol-based products produce a chemical reaction that result in the emission of light on contact with blood; lots of false positives

what does bluestar forensic do?

emits a blue glow when it comes into contact with blood

what is LCV and when should you use it?

Leucocrystal Violet (LCV)

Used to enhance detail of latent blood impressions 

what is amido black used for and what does it do? when should you use it?

• Used to enhance detail of latent blood impressions 

• Stains proteins in blood a blue-black color 

• use after LCV

what are the protocols for enhancement of impression evidence?

take photos before, take samples before, then test

what is the goal of bloodstain pattern analysis?

to find the direction of travel, angle of impact, and area of origin of a stain

what are the 4 types of bloodstains and what are examples of each?

passive: no external force applied

• flow

• pool

• drip

transfer: transferred from one place to another

• pattern transfer

• swipe

• wipe

• smear

projected/impact: external force applied

• arterial

• cast-off

• spatter

• expiratory

misc stains: don’t fit into any other categories

• fly spot

• void

• skeletonized

how is bloodstain directionality determined?

The tail of the blood droplet will point in the direction of travel.

how is angle of impact of a bloodstain determined? give an example:

The shape of the stain will be determined by the impact angle that the droplet made to the surface (ex: Lower angle (closer to 0 degrees) = longer stain)

what is roadmapping?

• Each pattern of interest is given a number or label. (ex: Pattern A) 

• Individual stains of interest within the pattern are given an additional identifier. (ex: Stain A-1). 

how does target surface effect bloodstains?

smooth surface: nicer stain

rough or porous surface: distorted stain

how do frangible vs non-frangible surfaces react with bullets?

frangible: crumbles or cracks

non-frangible: bends or stretches

how does metal react with bullets?

• The area surrounding a bullet hole can indicate directionality

• Paint on metal can chip off and create a bigger hole

how does glass react with bullets?

• External Impact produces concentric circles 

• Fractures in glass radiate from point of impact (radial fractures)

• The direction of fire (bullet path) is indicated by the beveling around the hole.

how is shot order determined?

Sequence of shots can be determined by the intersections of radial fractures; those of the second shot will terminate at those from the first shot

what is beveling?

• Beveling (coning effect) will be on the exit side

• Exit hole is bigger than entry because bullet will take material with it as it exits

what is the 3R rule?

Lines on Radial fracture edges form a Right angle on the Reverse side of the force

how does tempered glass react with bullets?

•  fractures into a mosaic pattern with no sharp edges 

• shots in tempered glass produce an irregular hole that is devoid of radial/concentric fractures. 

what are penetrating, perforating, and ricochet bullet defects?

Perforating:

• projectile enters a surface and then exits

• Exit holes are often larger and more irregularly shaped than entry holes.

Penetrating:

• projectile enters but does not exit a surface 

Ricochet:

• projectile deflects off a surface

Document the following 3 things for all bullet defects:

1. Dimensions (use scale in photos) 

2. Height (ex: from ground or floor) 

3. Distance from nearest corner or wall

what are the 3 types of ballistics and which are CSI most concerned with?

internal:

• involves firearm and ammunition evidence

external:

• considers the path and trajectory of a projectile after leaving the barrel of a weapon to its final impact

• CSI most concerned with this type of ballistics

terminal:

• involving the effect of a projectile on the human body.

when do you use a trajectory rod?

• Requires a primary & secondary bullet defect (perforating) 

• Bullet must be a straight trajectory

what is the angle of impact formula?

Angle of Impact = sin-1 (width/length)

what tools can be used to determine trajectory angles?

Trajectory rods, protractors, and angle gauges

who makes up a dive team?

team leader, line tenders, at least two divers

what are the search types for underwater scenes? describe them:

Circle

• Circumference of a circle around a fixed point at various distances (radii)

Arc/Pendulum

• Searcher moves back and forth in a pendulum fashion to one side of a fixed point 

Jackstay

• Two searchers move in opposite directions from fixed jackstays along a moveable jackstay 

Snag-line

• Weighted lines can be used to “snag” the target to speed up the search 

Compass

• An underwater compass is used for directionality and “kick cycles” for distance

how should evidence be marked in an underwater scene?

Evidence should be marked with a buoy affixed to the item or tied down in close proximity.

what are some photography concerns in underwater scenes?

• Distortion – objects will be magnified by 33% 

• Lighting/Coloration – limited visibility with only blue and green wavelengths in certain depths  

how should package evidence found underwater?

package items while they are submerged in water in which they were found in

what are some safety concerns in fire scenes?

• Unstable structures 

• Poor lighting 

• Significant debris 

• Hidden and damaged evidence

what is the goal in the investigation of a fire scene?

cause and origin

what can help investigators determine the area of origin in a fire scene?

Fire patterns, such as char and soot (high damage = longer exposure to heat)

what are the 4 types of fires?

• Accidental - unintentional 

• Natural – all acts of God 

• Incendiary – intentionally ignited 

• Underdetermined – not within an acceptable level of certainty

what can indicate an incendiary fire?

More than one area of origin or the presence of accelerant

what should you document from a fire scene? how should you approach this?

approach from least damage to most damage:

• Possible entry & exit points 

• Levels of fire damage 

• Fire patterns 

• Melted items 

• Possible ignition sources 

• Any signs of accelerants

how should you collect evidence from a fire scene?

• Collect samples of materials with possible accelerants 

• Package in an unlined paint can or nylon bag (no plastic) 

• Submit for analysis immediately. 

what is the evidence processing methodology?

ASSESS 

• Assess the circumstances 

OBSERVE 

• Cautiously examine the evidence

DOCUMENT 

• Document the evidence through notes, photos, and a sketch 

SEARCH 

• Methodically search the evidence 

COLLECT 

• Recover and package derivative evidence 

PROCESS 

• Perform physical or chemical processing 

ANALYZE 

• Submit evidence to Forensic Lab for additional testing

what are the evidence processing steps?

1. Preparation 

2. Documentation 

3. Visual Examination 

4. Physical and/or Chemical Processing 

5. Submittal to the Crime Lab or Property Room

what are the types of derivative evidence?

swabs and cuttings

how should you package derivative evidence?

• Assign an new item number 

• Seal package with tape 

• Initial & date seal

what is quality control and quality assurance?

• Quality Control (QC) refers to measures that are taken to ensure the product meets a specified standard of quality. Examples include positive and negative controls. QC is reactive and product-focused. 

• Quality Assurance (QA) refers to measures that are taken by a laboratory to monitor, verify, and document its performance. Examples include proficiency testing and auditing. QA serves as the functional check on QC within the laboratory. QA is proactive and process-focused.

what is Standard Operating Procedures (SOP)?

Standard Operating Procedures (SOPs) are written instructions to be carried out for the given task. Procedures are typically outlined in the Quality Manual and implemented and evaluated by the Quality Manager

how should you photograph a vehicle?

• all four sides

• area showing location

• license plate, VIN, dumper stickers

• damage

• wheels and tires

what documentation should you take from tires?

• size info

• DOT number

• track width (inside to inside, outside to outside)

• wheelbase

what is hot shock? what does it indicate?

• Bulb filaments soften at hot temperatures and can stretch instead of breaking upon impact, known as “hot shock”.  

• The presence of hot shock is evidence that a headlight or brake light were on at the time of impact

what evidence from a vehicular crime may be present on a body?

• Blunt force trauma 

• Seat Belt marks 

• Pedal marks 

• Airbag injuries 

• Tire marks 

• Trace materials 

• Paint transfers 

• Trace hairs/fibers

how should you photograph a tire impression?

• First the overall length of the impression is documented and photographed using cones 

  • Place a cone at the 

    • Beginning 

    • End 

    • Along the path if the track is long

• Photograph the entire impression overlapping the previously photographed impression approximately 1 – 2 ft segments (7.5 ft = full tire)

  • Take the same four photographs as you did for the footwear impression 

    • Repeat For each segment along the impression