chp. 2 the crime scene part ii 1 chp. 2 2 please do now state 4 factors that determine how a crime...

Chp. 2

Chp. 2

The Crime Scene

Part II

1

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Please Do Now

State 4 factors that determine how a crime scene is searched?

State 4 things that an investigator might be looking for at a crime scene.

Please list them in your composition book.

Photo:http://www.usatoday.com/news/health/2002-10-30-evidence-usat_x.htm

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CRIME SCENE SEARCH PATTERNS

How to conduct a crime scene search depends on

One person should supervise and coordinate the collection of evidence

1. Location of the scene2. Time of day / weather3. Type of crime4. Details concerning events

of the crime5. Number of people

available for the search6. Available equipment

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TYPES OF CRIME SCENE SEARCH PATTERNS

Line or strip method —best in large, outdoor scenes Grid method —basically a double-line search;

effective, but time-consuming Zone method —most effective in houses or buildings;

teams are assigned small zones for searching Wheel or ray method —best on small, circular crime

scenes Spiral method —may move inward or outward; best

used where there are no physical barriers

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VEHICLE SEARCHES

Hit-and-run cases Outside and undercarriage of car are examined

Look for cross-transfer of evidence between car and victim (blood, tissue, hair, fibers, fabric impressions, pain, broken glass,…)

Homicide, burglary, kidnapping All areas of the vehicle, inside and outside, are

searched

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***Common Types of Physical Evidence

Blood, Semen & Saliva

Documents

Drugs

Explosives

Fibers

Fingerprints

Firearms & Ammunition

Glass

Hair

Impressions

On a whiteboard list 10 types of physical evidence.

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Common Types of Physical Evidence

Organs & Physiological Fluids

Paint

Petroleum Products

Plastic Bags

Powder Residues

Serial Numbers

Soil and Minerals

Tool Marks

Vehicle Lights

Wood & Vegetative Matter

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WHAT EVIDENCE SHOULD BE COLLECTED?

Body Blood Hair Fibers Clothing Fingernail scrapings

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EVIDENCE FROM A BODY

The search for physical evidence extends beyond the crime scene to the autopsy room of a deceased victim.

Medical examiner or coroner carefully examines the victim to establish a cause and manner of death.

As a matter of routine, tissues and organs will be retained for pathological and toxicological examination.

Arrangements must be made between the examiner and investigator to secure a variety of items that may be obtainable from the body for laboratory examination.

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EVIDENCE FROM A BODY

The following are collected and sent to the forensic laboratory:

1. Victim’s clothing 2. Fingernail scrapings 3. Head and pubic hairs 4. Blood (for DNA typing purposes) 5. Vaginal, anal, and oral swabs (sex crimes) 6. Recovered bullets from the body 7. Hand swabs from shooting victims (for gunshot residue analysis)

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COLLECTING AND PACKAGING EVIDENCE

One individual should be designated as the evidence collector to ensure that the evidence is collected, packaged, marked, sealed, and preserved in a consistent manner

Each item must be placed in a separate container, sealed, and labeled

Most fragile is collected and packaged first Different types of evidence require specific or special

collection and packaging techniques The body is the property of the coroner or medical examiner.

The collection of evidence on the body is done by that department.

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What evidence can you find?

A styrofoam cup and a Sprite? Bottle (each circled). Also one shoe and what may be a cub scout cap.

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Integrity of evidence must be maintained (prevent physical evidence from changing on its way to the crime lab)

Changes could occur through: Contamination Breakage Evaporation Accidental scratching Bending Loss through improper or careless packaging

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Do NOT remove evidence (such as blood, hair, fibers, soil particles,etc.) adhering to clothes, weapons, or other articles

Send the entire object to the lab for processing

If evidence is sticking to an object in a precarious way, then it might have to be removed and packaged

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A detective holds the pliers found in Scott Peterson’s fishing boat. The hair seen stuck to the end of the pliers is the sole piece of physical evidence presented by the prosecution.

http://www.search.com/reference/Scott_Peterson

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http://www.wksu.org/news/story/20391

Blood evidence found on pants

Note: If bloodstained material is stored in airtight containers, moisture buildup may encourage mold growth, which can destroy evidential value of blood.

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PACKAGING EVIDENCE

Each different item or similar items collected at different locations must be placed in separate containers. Packaging evidence separately prevents damage through contact and prevents cross-contamination.

The well-prepared evidence collector will arrive at a crime scene with a large assortment of packaging materials and tools ready to encounter any type of situation.

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PACKAGING EVIDENCE

Forceps and similar tools may have to be used to pick up small items.

Unbreakable plastic pill bottles with pressure lids are excellent containers for hairs, glass, fibers, and various other kinds of small or trace evidence.

Alternatively, manila envelopes, screw-cap glass vials, or cardboard pillboxes are adequate containers for most trace evidence encountered at crime sites.

Ordinary mailing envelopes should not be used as evidence containers because powders and fine particles will leak out of their corners.

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PACKAGING EVIDENCE

Small amounts of trace evidence can also be conveniently packaged in a carefully folded paper, using what is known as a “druggist fold.”

Although pill bottles, vials, pillboxes, or manila envelopes are good universal containers for most trace evidence, two frequent finds at crime scenes warrant special attention.

If bloodstained materials are stored in airtight containers, the accumulation of moisture may encourage the growth of mold, which can destroy the evidential value of blood.

In these instances, wrapping paper, manila envelopes, or paper bags are recommended packaging materials.

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PACKAGING

Most items should be packaged in a primary container and then placed inside a secondary one. These are then placed inside other containers such as paper bags, plastic bags, canisters, packets and envelopes depending on the type and size of the evidence.

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Please Do Now

What is chain of custody? Why is it important?

Please answer in your composition book.

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CHAIN OF CUSTODY

Chain of Custody—A list of all persons who came into possession of an item of evidence.

Continuity of possession, or the chain of custody, must be established whenever evidence is presented in court as an exhibit.

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CHAIN OF CUSTODY

Adherence to standard procedures in recording the location of evidence, marking it for identification, and properly completing evidence submission forms for laboratory analysis is critical to chain of custody.

EVERY person who handled or examined the evidence and where it is at all times must be accounted for.

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CHAIN OF CUSTODY

There must be a written record of all people who have had possession of an item of evidence.

A minimum record would show:1. Collector’s initials

2. Location of evidence

3. Date of collection

• If evidence is turned over to another person, this transfer MUST be recorded in notes and other appropriate forms

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CRIME SCENE RECONSTRUCTION

Stages Data collection Hypothesis formation Examination, testing and analysis Determination of the significance of

the evidence Theory formulation

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OBTAINING REFERENCE SAMPLES

Standard/Reference Sample—Physical evidence whose origin is known, such as blood or hair from a suspect, that can be compared to crime-scene evidence.

The examination of evidence, whether it is soil, blood, glass, hair, fibers, and so on, often requires comparison with a known standard/reference sample.

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When forensic scientists examine DNA in the lab, each sample appears as a unique sequence of dark bars.

Patterns of bars are compared to find a match.

In the hypothetical example shown here, which suspect left some DNA at the crime scene? #2

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Autoradiograph from an actual rape case showing the DNA profiles for one VNTR locus.

The lanes marked "M" show a "ladder" of DNA fragments of known sizes.

These are loaded onto the gel to provide an internal ruler--allowing the sizes of the VNTR alleles to be estimated more accurately.

Is there a match?

YES, the DNA profile of defendant 1 and forensic sample.

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INVESTIGATORS

“The wise forensic investigator will always remember that he must bring all of his life experiences and logic to find the truth. This means common sense, informed intuition, and the courage to see things as they are. Then he must speak honestly about what it adds up to.”

—Dr. Henry Lee

Chief Emeritus for Scientific Services and theformer Commissioner of Public Safety for the state of Connecticut

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Submit Evidence to Lab

Evidence submitted to lab in person or by mail shipment

Usually an evidence submission form accompanies the evidence (see p. 57)

Specify the type of examination is needed for the evidence

New evidence may be uncovered during the examination

Include a list of evidence submitted on the evidence submission form

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MURDER SCENE

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MURDER SCENENed Doheny, Feb. 16, 1929

What do you see?

Ned Doheny, son of oil magnate Edward Doheny, lies dead in the foreground; the body of his friend and assistant Hugh Plunkett is in the hallway beyond. Los Angeles authorities immediately blamed Plunkett in the murder-suicide

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Nicole Simpson / Ron Goldmanmurder scene, June 12, 1994

http://wordpress.com/tag/our-blood/feed/www.cnn.com

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THE CORPSE

“The way I see it, being dead is not terribly far off from being on a cruise ship. Most of your time is spent lying on your back. The brain has shut down. The flesh begins to soften. Nothing much new happens, and nothing is expected of you.”

—Mary Roach. Stiff. W. W. Norton & Company. 2003

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MURDER SCENE

Most important piece of evidence is the victim’s body

Forensic pathologist May be aided by:

Forensic anthropologists

Forensic entomologists

Forensic pathology: study of medicine as it relates to the application of the law, especially criminal law

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FORENSIC PATHOLOGIST

Forensic Pathology involves the investigation of unnatural, unexplained, or violent deaths. Forensic pathologists in their role as medical

examiners or coroners are charged with determining cause of death.

The forensic pathologist may conduct an autopsy which is the medical dissection and examination of a body in order to determine the cause of death.

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MEDICAL EXAMINER AND THE CORONER

Medical examiner— a medical doctor, usually a pathologist and is appointed by the governing body of the area. There are 400 forensic pathologists throughout the U.S.

Coroner — an elected official who usually has no special medical training. In four states, the coroner is a medical doctor.

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MEDICAL EXAMINER’S RESPONSIBILITIES

Identify the deceased Establish the time and date of death Determine a medical cause of death—the injury or disease that resulted

in the person dying Determine the mechanism of death—the physiological reason that the

person died Classify the manner of death

Natural Accidental Suicide Homicide Undetermined

Notify the next of kin

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FORENSIC PATHOLOGIST

4 broad determinations to be made:

A. Cause of Death – medical diagnosis denoting disease or injury

B. Mechanism of Death – altered physiology by which disease/injury produces death (arrhythmia, exsanguination)

C. Manner of Death

1. Homicide 3. Accidental 5. Undetermined2. Suicide 4. Natural Causes

D. Time of Death

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NATURE OF DEATH

One can die of a massive hemorrhage (the mechanism of death) due to a gun shot wound through the head (cause of death) as a result of being shot (homicide), shooting yourself (suicide), dropping a gun and it discharging (accident), or not being able to tell which (undetermined). All of which are manners of death.

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CAUSE and MANNER OF DEATH

Autopsy: medical dissection and examination of body to determine the cause of death

Manner of death: video 1. Natural 2. Homicide Click to see the real CSI: Crime Autopsy

3. Suicide 4. Accidental 5. Undetermined

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THE BODY FARM

Click toSee video

Video 2

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THE BODY FARM

3 acres of land owned by the University of Tennessee

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THE BODY FARM

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THE BODY FARM

Day 1 Day 2 Day 3

Day 5Day 4

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THE BODY FARM

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ESTIMATING TIME OF DEATH

Can estimate time of death from

• body temperature (algor mortis)

estimate: [98.4 oF – rectal temp] X 1 hour

1.5°F

• insect action (forensic entomology)

• stomach contents (stage of digestion)

• last known activity (last sighting, newspaper/mail)

• normal postmortem change

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ALGOR MORTISThe Temperature of Death

Loss of heat by a body (a general rule, beginning about an hour after death, the body loses heat by 1 to 1 1/2 degrees Fahrenheit per hour until the body reaches the environmental temperature).

Due to lack of cellular respiration Temperature in 2 ways: rectal and/or liver temperature Variables:

• Environmental conditions

• Person’s state of health at time of death

• Naked versus clothed bodies

• Lightening, electrocution and asphyxia

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RIGOR MORTISThe Stiffness of Death

results in the shortening of muscle tissue and the stiffening of body parts in the position at death

occurs within the first 24 hrs. and disappears within 36 hrs.

Due to build up of lactic acid after respiration ceases

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RIGOR MORTIS

Body warm not stiff less than 3 hours

Body warm stiff 3-8 hours

Body cool stiff 8-36 hours

Body cool not stiff more than 36 hours

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LIVOR MORTISThe Color of Death

(postmortem lividity) results in the settling of blood in areas of the body closest to the ground after heart stops

begins immediately on death and continues up to 12 hrs.

Latin: livor—bluish color; mortis—of death

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LIVOR MORTISThe Color of Death

Lividity indicates the position of the body after death

When lividity becomes fixed, then the distribution of the lividity pattern will not change even if the body’s position is altered.

Lividity usually becomes fixed between 12- and 15 hours after death

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LIVOR MORTIS

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DESICCATION

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After Death Processes

Algor mortis• Change in temperature after death• Most useful indicator of the time of death during first 24 h

• Roughly 1.5ºC/hourLivor mortis• Settling of blood in the body gives off a bluish-purple colorRigor mortis• Stiffening of the muscles after deathAutolysis• Tissue breakdown by the body's own internal chemicals and enzymesPutrefaction• The breakdown of tissues by bacteria. These processes release gases that are the chief

source of the characteristic odor of dead bodies. Mummification• Dehydration or desiccation of tissuesSkeletonization• Removal of soft tissue. Occurs largely as a result of insects and animalsAdipocere• Formation of a waxy substance due to the hydrogenation of body fat. A moist, anaerobic

environment is required for the formation of adipocere.

video

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POTASSIUM EYE FLUID MEASUREMENT

After death, red blood cells break open and potassium enters the (ocular) vitreous fluid slowly.

The potassium level rises predictably after death

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PEOPLE IN THE NEWS

Dr. Michael M. Baden is a renowned pathologist and was the Chief Medical Examiner in NY City and for Suffolk County.

Dr. Baden was on the panel that investigated the assassinations of president John F. Kennedy and Dr. Martin Luther King, Jr. He has been involved as an expert in forensic pathology in many cases of international interest including:

• The remains of Tsar Nicholas of Russia and his family• The Claus Von Bulow murder trial• Expert witness for the defense in the O.J. Simpson trial• Re-autopsy of Medgar Evers, Civil Rights leader• Re-examination of the Lindberg Kidnapping and murder• Autopsies of the victims of TWA Flight 800

Dr. Baden is the host of HBO’s Autopsy series and is featured on many of the crime talk shows.

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MORE INFORMATION

For additional information on crime scene investigation, check out Court TV’s Crime Library:

www.crimelibrary.com/criminal_mind/forensics/crimescene/5.html

On Michael Baden and the autopsy: www.crimelibrary.com/criminal_mind/forensics/autopsy/1.html

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FORENSIC ANTHROPOLOGY

concerned primarily with the identification and examination of human skeletal remains

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male

male female

female

Gender ?

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White African American Native American

Race ?

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Please Do Now

Explain this sign.

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FORENSIC ENTOMOLOGY

Jerry Butler, entomology professor with the University of Florida's Institute of Food and Agricultural Sciences, examines Hairy Maggot Blow fly larvae retrieved from a murder victim.

Butler, one of only five forensic entomologists in Florida and about 100 worldwide, uses larvae to help police establish the time and place of death.

AP photo:Thomas Wright, University of Florida/IFAS

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FORENSIC ENTOMOLOGY

study of insects and their relation to a criminal investigation, commonly used to estimate the time of death.

Maggots eating a dead cow

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FORENSIC ENTOMOLOGY

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FORENSIC ENTOMOLOGY

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