Crime Scene Investigation IAI

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Fish/Miller/Braswell

Final analysis is done where?

In the courtroom

Major Goals of a Crime Scene Search

* The recongnition and identification of physical evidence
* The collection and proper preservation of the evidence
* Reconstrutction of the crime
* To assist detectives in forming a theory about the crime

The job of the CSI in "forensic science"

Is to properly recongnize, identify, collect, and preserve those pieces of evidence that begin the process known as justice.

CSIs are responsible for what two of the four steps in the admissiblity of phiysical evidence for court?

recognition and collection

Physical evidence leads to the linkage of...

the victim, perpetrator and the scene

Four Major Factors that Determine the Value of Physical Evidence

Recognition-the CSI must have the knowledge and understanding to recongnize potential items of physical evidence located at the crime scene
Collection-Utilizing the appropriate skills and following accepted protocols to gather and preserve the physical evidence
Testing Procedures-Application of acceptable scientific procedures to analyze the physical evidence
Courtroom Presentation-Qualifications of the witnesses to provide objective reports on the forensic analysis of the evidence

Forensic Archeologist

Utilizes archaeological recovery techniques at scenes of mass graves or exhumations

Forensic Botanist

Can aid in determining time since death or assist in placing a suspect or victim at a location by studying the anatomy of plant evenidence

Forensic Entomologist

Can evaluate the life cycle of insects found at the scene or on the body of a victim to assist in establishing investigative leads such as the movement of a body after death, manner of death, and the postmortem interval

Forensic Odontologist

Dentist with special training in the evaluation and handling of dental evidence, including bitemark comparison and the identification of victims/suspects

Forensic Pathologist

A medical doctor with additional specialty training in determination of injuries and disease that cause death

Medical Examiner

A medical doctor with five or more years of specialized training in recognition of the cause and manner of death

Coroner

An eleted or appointed official who conducts death investigations. the coroner is not required to have a medical background and his/her duties are dictated by jurisdiction.

FSAB

Forensic Specialties Accreditation Board- provides accreditation to those certifying bodies that meet stringent requirements for training, education, experience, and testing of individual forensic scientist and specialist.

the duty of the expert witness is to

educate the jury and provide testimony using terminology that is easily explainable and not misunderstood.

Essential elements of exper witness testimony

Clarity, simplicity, and honesty

expert witness testimony may be challenged in the following ways:

*the case may not require the expertise
*Basic qualifications and ability to give an opinion in the field at issue
*Insufficient education or experience to have anything of value to offer (no vaule added)
*the methodology utilized to support the opinion may not be scientifically sound or capable of supporting the profered opinion
*The methodology may be scientifically sound, but the opinion based on the method is not sufficiently derived from that scientific methodology

Acts of commission

Intentional

Acts of omission

unintentional

O.J. effect

discrediting the chain of evidence, the scientists, or the science is known as the OJ effect and has become a key defense technique

Physical evidence is valuable in many aspects and can reveal data that will aid the investigation by:

*Providing essential information on the facts of the case-corpus delicti
*Revealing the modus operandi (MO)-the preferred method of operation
*Demonstrating linkages between the vicitm, suspects, locations, and objects
*Proving or disproving witeness statements
*Identifying a suspect through DNA or other individualization
*Classifying unknown substances
*Reconstructing the crime scene-how a crime was committed
*Developing investigative leads

Corpus delicti

facts of the case

MO-Modus Operandi

the preferred method of operation

Class characteristics

physical evidence that cannot be related to a common origin with a high degree of certainty, therefore it can only be associated with a group and never a single source

Indivdual characteristics

are distinct differences in the physical evidence that allow it to be associated with a single source and allow the examiner to determine the uniqueness of any single object or piece of evidence

Associative evidence

items of physical evidence located during a crime scene search can be used to demonstrate linkage or to "associate" the victim to the suspect or to a particular location

What ammendment protects against unreasonable search and seizure

Fourth amedment

Mincey v. Arizona

dictated what actions law enforcement personnel are authorized to take without first obtaining a warrant

Items that can be obtained without obtaining a warrant

1. Seach the scene for rictims and render aid in areas where a victim could resonably be found
2. Enter the scene to search for perpetrators (only in areas where a suspect could be located)
3.While officers are legally in a location performing either of the two aforementioned actions, they may swize items of evidentiary nature that are in plain view-however, this should only occur in exigent circumstances, such as an unsecured weapon

Transient evidence

is defined as physical evidence that may be lost forever if not immediately preserved

Fruit of the poisonous tree

If the physical evidence is tainted then any subsequent information derived from that evidence would also be tainted

Frye v. United States

rejected the admission of a polygraph test on the basis that the reliability of the intrument had not been proven.

Frye test

established the criteria that define judicial acceptance of scientific advances. Basically, the ruling requires expert testimony to be based on scientific principles or procedues that have already been generally accepted winthin the scientific community. Courts will hear testimony from experts in the field as well as consider scientific papers before determining the acceptability of a technique

Rule 702

Federal court system guideline when dealing with the admissibility of expert tesimony relating to scientific analysis of physical evidence. The judge is responsible for the determination of qualifications of an expert witness and if they can offer an opinion based on knowledge, skill, training, or education and experience. Only apply to fedeal court proceedings but many state courts have adopted these guidelines.

Daubert guidelines

the court will require proof that the scientific basis underlying the opinion is generally accepted in the scientific community and is relevant and reliable. Judges must assume the responsibility of becoming the gatekeeper in determining the admissibility of scientific evidence.

"Relevant and Reliable" standard of Daubert

Prior to acceptance of expert testimony the jusdge must determine if the reasoning or methodolog underlying the testimony is scientifically valid and can be applied to the facts at issue

Chain of custody

usually referes to the documentation of the location of all physical evidence at all times

Every action must be documented in what ways...

notes, photographs, sketches, and reports

The purpose of documentation is to

create a permanent record of the condition of the crime scene and the physical evidence

Four stages that must be completed during documentation include:

1. taking notes 2. videography 3. photography 4. sketching

Photo log indicates:

time and date, roll number, camera settings, distane to the subject, and a brief describtion.

ASLD

American Society of Crime Lab Directors

Is the control included in final laboratory results?

the control will be documented and included in final laboratory results

PPE

Personal Protective Equipment

SCBA

Self-contained breathing apparatus

When establishing boundaries should they be smaller or larger?

Always secure a larger area and then reduce the area as additional information is determined

Cross contamination

transfer of material between two or more sources of physical evidence

Safety Measures

*No eating, drinking, smoking, or using cell phones in the crime scene
*Be alert for biological, chemical, environmental, or mechanical hazards
*Watch for sharp objects such as hypodermic needles, knives, razors, broken glass, nails, exposed metal, or other objects
*Do not use the bathrooms at the crime scene
*Never pick up broken glass with your hands. Use a brush and dust pan, tongs, forceps, or tweezers and place the pieces in a secure container
*Place all syringes, needles, and other sharp objects in a puncture resistant container with a biohazard waring label. Never recap or place covers such as erasers over hypodermic needles.
*When searching confined spaces, use mirrors, flashlights, and other tools before placing your hands in the space. Do not overlook the potential for poisonous spiders and/or snakes in narrow or confined dark areas
*Always use caution in unknown environments. Exotic pets may pose a hazard-poisonous snakes, scorpions, and spiders can startle the unsuspecting CSI
*Always wash your hands or other skin surfaces thoroughly and immediately if you come in contact with any body fluid. The universal decontamination solution is a diluted solution of bleach 1:10 or 70% isopropyl alcohol

Types of PPE

Gloves, Tyvek suits, shoe covers, and eye and respiratory protection are essential for ensuring personal safety.

OSHA

Occupational Safety and Health Administration

Bloodborne pathogens

are infectious disease causing microorganism that may be found or transported in biological fluids. Treat all human blood and body fluids as though they are potentially infectious.

Fluids other than blood that may contain pathogens include:

urine, feces, tears, sweat, nasal secretions, saliva, semen, vaginal secretions, breast milk, and vomitus. Human body also contains cerebral spinal fluid as well as synovial (joints), Pleural (chest), peritoneal (abdomen), amniotic and pericardial (heart) fluids that can carry bloodborne pathogens.

Most common bloodborne pathogens

Human Immunodeficiency Virus (HIV-AIDS), Hepatitis, rabies, and sexually transmitted diseases.

Barrier protections include

disposable gloves, lab coats or coveralls, and eye and face protection.

Does PPE guarantee total protection from bloodborne pathogens

PPE does not reduce the hazard or guarantee total protection-it is used to minimize the exposure or contact with potentially hazardous materials

Nitrile gloves

Chemical resistant

When should you change gloves

frequently to reduce the possibility of cross contamination. Immediately if they become punctured or torn

A face mask must be used with what?

with goggles or safety glasses-it does not provide adequate protection if used alone

Most ccommon route of exxposure for most matterials that are health hazards??

Inhalation

Airborne contaminants may be

dust, aerosol, smoke, vapor, gas, or fumes

A disposable dust/surgical mask will fillter what?

will filter out large particulate matter, but does not provide repiratory protection from chemical vapors or biological contaminants.

What type of respirator is required for the CSI to work in a potentially contaminated enviornment?

Air purifying respirator (APR)

HEPA

High-efficiency particulate air (HEPA) filter attached to the APR provides additional protection as air is drawn through the filter by the wearer.

Indirect contamination of your face can occur how?

Touching or rubbing your face with contaminated gloves

Disposable lab coats or Tyvek coveralls provide protection against what?

Biological contamination

Light sourcce eyewear must guard against what?

The maximum operating wavelength of the laser source

Cyanide has what odor?

Almond ordor

Rotten eggg odor indicates?

Hydrogen Sulfide. Hydrogen sulfide is more toxic than hydrogen cyanide

HazCom

Hazard communication

For HazCom yourr employers mmust

1. Develop, implement, and maintain at each workplace a written hazard communication program
2. Compile a list of every chemical that is in use with MSDSs on each
3. List the methods or procedures the employeee will perform that iincolves thhe use of chemicals. Precautionary measures must be included in the Hazzcom program. Written protocols must be establiished that ensure that appropriate emergenccy procedures are in place in th event of an acciident.

HMIS

Hazardous Materials Identification System-chemicals must be properly labeled with appropriate hazard warnings labels

Color standards for HMIS

blue=health hazard
red=flammability
yellow=reactivity
white section=special info ie what PPE to wear

Numarical system for HMIS

0 (no hazard)-4 (Severe hazard) which indicates the severity of the hazard. label also must include OSHA threshold limitys, if it is a potential carcinogen, proper emergency and first aid procedures and name and contact info of the chemical mau

Routes of exposure

Inhalation, ingestion, skin contact/absorption, and injection

Acute effects

occur rapidly as a result of short term exposure and are of short duration

Chronic effects

occur from exposure over time and/or of long term duration

PPE must be dsposed of in

biohazard bags

What should be in a CSIs Notes?

* time and date of notification/how notified/by whom
*Time of arrival on the scene, weather conditions, climate, lighting, outdoor and indoor temp
*Fixtures, doors, windows, gates, and their condition (open/shut locked/unlocked)
*Odors and other changing or eteriorating items (we footprints, melting ice cream)
*Identification and appearence of persons in the crime scene
*Location and condition of items within the scene
*Items that were moved or changed, by whom, and for what purpose
*Appliances (off-on, hot-cold)
*Peronal items-either miss or in place (wallet, keys, shoes)
*what tasks were performed and who completed those tasks

General rule of the initial walkthrough/preliminary assessment

Look-but don't touch

Gun and powder create blowwback on the rear of the gun, which deposits what?

primer, lead, barium, and atimony

Can be tested by swabbing the suspect's hands by swabbing with

use a cotton swab moistened with nitric acid. GSR can remain on the hands for up to 6 hrs after after a weapon has been fired.

Impression evidence

fingerprints, palm prints, nose or ear prints, toolmarks, and foot wear/tire impressions

Four findings that can be related to the examination of bitemarks, provided a suspect has been identifed:

*Definite-to the exclusion of all others
*Consistent-no features present that will exclude the suspect
*Possible-due to the nature of injury, ubable to positively confirm or exclude the suspect
*Exclusionary-Definitely not made by the suspect

Dental Stone

composed of calcium sulfate (plaster of paris) with potassium sulfate for greater hardness

Forensic biology

is the study of life and icludes both cellular and microbiology subspecialities

serology

analysis of the properties and effects of serums (bood, semen, saliva, sweat, or feal matter

Toxicology

the study of body fluids, tissues, and organs for the presence of drugs or poisons

Presumptive tes

screening test is the first of two processes the lab performs to check for the presence of a drug or poison

Confirmatory test

is the second step. the most common process for this is gas chromatography-mass spectrometry (GC/MS)

Main sources of evidence submitted for toxicological analysis

urine, blood, hair saliva, and sweat

Common locations (of the body) where DNA can be easily obtained

blood, bone, urine, dandruff, ear wax, fingernails, skin, sweat, hair, seminal fluid, vaginal or rectal cells, teeth.

DNA is

an organic compound found in the chromosomes of the nuclei of cells

mtDNA

Mitochondrial DNA is transmitted only through the maternal line

CODIS

Combined DNA Index System

Advantages of DNA Analysis

*Identify a suspect
*Implicate or eliminate a suspect
*Place a known individual at a crime scene
*refute a claim of self defnse
*Put a wapon in a suspect's hand
*Change a suspect's story from an alibi to one of consent
*Analyze unidentified remains
*resolve paternity/maternity cases
*Link related cases
*Provide leads in cold or unsolved cases
*Be used to appeal convictions

What should be documented when presumtive blood tests are done?

location, time, date, name of CSI performing tests, and specific test that were conducted

Semen is composed of

95% fluid and 5% spermatozoa

PSA

Prostate-specific antigen, found only in semen

SANE

Sexual assault nurse examiner

PERK kit contains

physical evidence recovery kits contain swabs, slides, test tubes, combs, and paper envelopes

EDTA

preservative/anticoagulant

Chemiluminescense

is the emission of light without the emission of heat as the result of a chemical reaction

Bloodstain pattern analysis

is the examination of the shapes, locations, and distribution patterns of bloodstains, in order to provide an interpretation of the physical events that occured at the crime scene

How much bloodmust be lost to produce irreversible shock and death?

40% of the total volume of blood. Men have 5-6 liters of blood in the body, women have 4-5 liters

If a blood drops fall at an angle less than 90 degrees is will be

more oval or elongated

Narrow end of tail of a bloodstain usually points...

in the direction of travel

Impact spatter

bloodstains smaller than a freely foaming drop

Low velocity impact spatter

results when blood is traveling at about 5 feet per second. This type of blood spatter averages about 3mm or more in diameter.

Medium velocity impact spatter

creats smaller spatter and is produced when velocity of the force is between 5-25 feet per second. Blunt trama may result in MVIS or stabbing that can range from 1mm to 3mm in diamter

Cast-off

are created by blood being propelled by a force greater than gravity from being flung off a blood object

High velocity impact spatter

occurs when the velocity of the force is above 100 foot per second and is generated by a gunshot, explosion, power tool, or automobile accident. Almost mist like smatter and less than 1mm in size

Passive stains

are created by drips, flows, pools, and saturation stains

Impact and projected spatter stains

result of splashes, cast off, arterial spurt, or gushing, as well as from the impact itself and expiration

Splash patterns

may indicate movement of a victim after being injuried. They are created when large columes of blood are falling from a source such as an injury.

Transfer stain

is created when a wet blood surface comes in contact with a seondary surface. a recongnizable image of all/a portion of the orginal surface may be observied in the patter. Transfer stains occur from sipes, swipes, transfers, or contacts

Wipe patterns

are observed when a perpetrator attempts to clean up a crime scene by wiping away blood with a cloth

Contact stains

occur when a bloody fingerprint or shoe print is left at the site of the attack

Void pattern

is created when n item is removed from the area after bloodstain spatter has been created

Skeletonized stains

occur when the perimeter of the stain has dried and the center has flaked away, leaving the visible outer ring

what can a bloodstain pattern analyst tell you

*Position of victim or suspect
*Evidence of a struggle
*Areas where stains are absent
*In line stain patterns created by cast off
*sequence of events
*How many impacts and from what direction
*whether stains or patterns are sonsistent with statements
*May determine information that eliminates other avenues of investigation by identifying whose blood is where

Lands and grooves

striations when a bullet travels through the barrel of a gun

Two categories of firearms

handguns and long guns

Ballistics

the study of a projectile in motion

Questions a firearms examiner can answer

*What type and caliber of weapon was disccharged?
*What angle and distance was the gun fired?
*what was the sequence of events?
*was the firearm function properly

Bloodstain pattern analysis is a science because

the stains and patterns can be reporduced under controlled circumstances

Bullets are generally made from

lead, which is a soft heavy metal

Jacket is usually

brass, copper, or an alloy and this keeps the bullet from jamming, melting, or disintegrating.

Firearms identification is primarily concern concerned with

the determination of whether a bullet, cartridge casing, or other ammunition was discharged, extracted, or ejected from a specific firearm.

Striations

scratches created by lands and grooves of the barrel

Class characteristics of bullets

*Caliber
*Number of lands and grooves
*width of lands and grooves
*Degree of twist
*Direction of rifling twist

Class characteristics of cartridges discharged in guns

*Caliber
*Firing pin location
*Relative location of extractor/ejector
*Primer type
*Extractor and ejector marks
*Firing pin size and shape

Three conclusions the firearms examiner can render concerning the comparison of a suspect weapon to recovered bullets:

1. The bullet was fired by the suspect gun
2. Class characteristics and striations do not match; therefore, the suspect gun is excluded
3. Class characteristics match, but striations do not; therefore the resuults are inconclusive.

After doucmenting the firearms' position do what?

examine the firearm for trace/transfer evidence, such as latent fingerprtins, hair and fiber, toolmarks (defaced serial numbers, and blood spatter evidence.

If the firearm is a revolver indicate...

the position of the cylinder as well as the chamber from which wach cartridge or cartridge casing was unloaded

why photograph the front and back of the cylinder?

this will allow you to document the cylinder GSR flash rings (halos) around the chambers on the front of the cylinder as well as the cartridge head stamps that indicate caliber and make of the firearm.

All packages containing ammunition must be labeled with?

"LIVE AMMUNITION"

Bullets or bullet fragments may be classified as...

projectiles, components from a cartridge, or deformed bullets.

On the container containing bullets/bullet fragements indicate

the souce of each item, affix appropriate labels, and seal the evidence package.

what should be done before attempting to remove shot material

Take meaurements, videotape, and make written notes before attempting to remove the shot material

Firearm recovered underwater should be packaged...

in water in a sealed plastic bag to keep the weapon from rusting. This bag should be packed in a sturdy box and properly labeled and sealed. Then it should be hand delivered to the laboratory to prevent any damage occuring to the weapon or packaging.

Fired cartridge casings may contain marks left by....

the firing pin, ejector, extractor, magazine, chamber, and breech face

What information can the wadding or pistons bring to light

make of the shotgun shell used, gauge of the gun, approximately position from which the shot was fired, and the size of the shot that was loaded in the shell

You can expect to finding wadding or pistons with a distance of _ from where the shot was fired?

0 to 40 feet

Chemical test for lead

Sodium rhodizonate test. the solution should preferable be mixed fresh at the scene because it has a very short shelf life. Positive result is a dark red to purplish color

Chemical test for copper

dithio-oximide

When should field tests not be done of ballistic evidence?

should not be performed on possible ballistic damaged clothing in the field. Better perofrmed in a laboratory.

Other questions that may arise with ballistic damage evidence are:

*Which damage indicates and entrance or an exit hole?
*what is the sequence of events and shots fired?

Other facts to consider when formulating the discharged shell casing pattern tests:

shooter's height or suspected height, shooter's hand position and grib, the angle, trajectory, and sequence of shots, any movement of the shooter, weather conditions, and type of ground surface at the scene

Impact side when a bullet hits a surface

Imapct side will cause the impacted surface to come under compression

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