forensic pathology 2007(2)

PETER NG, UST

FORENSIC PATHOLOGYFORENSIC PATHOLOGY

PETER P. NG, PETER P. NG, M.D.,Ph.DM.D.,Ph.D., LL.B.., LL.B.UST FACULTY OF MEDICINE AND SURGERY

UST FACULTY OF CIVIL LAWUST GRADUATE SCHOOL

PETER NG, UST


• FORENSIC SCIENCE– FORENSIC SEROLOGY– FORENSIC CHEMISTRY– FORENSIC GENETICS– FORENSIC BIOCHEMISTRY/MOLECULAR

BIOLOGY– FORENSIC ANTHROPOLOGY– FORENSIC ODONTOLOGY– FORENSIC ENTOMOLOGY– FORENSIC BOTANY

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• FORENSIC MEDICINE– FORENSIC PATHOLOGY– FORENSIC OBSTETRICS – FORENSIC GYNECOLOGY– FORENSIC PEDIATRICS– FORENSIC PSYCHIATRY– FORENSIC PHARMACOLOGY– FORENSIC ENT/OPTHA

• MEDICAL JURISPRUDENCE

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““CSI CSI –– Crime Scene InvestigationCrime Scene Investigation””

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Fold down or cross-projection sketch.Room is unfolded as if it is a cardboard box.Each wall is representedas a flap extending fromthe floor.

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PHYSICAL EVIDENCE PHYSICAL EVIDENCE TRIANGLETRIANGLE

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Person of Historical SignificancePerson of Historical SignificanceEdmond Locard (1877-1966)

French professorConsidered the father of criminalisticsBuilt the world’s first forensic laboratory in France in 1910

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The The LocardLocard Exchange PrincipleExchange Principle• Every time an object comes into contact with

another object, it either leaves a portion of itself or takes a portion of the other object with it

– Every contact leaves its trace

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CRIME SCENE TEAMCRIME SCENE TEAMA group of professional investigators, each trained in a variety of special disciplines.Team Members

First Police Officer on the sceneMedics (if necessary)Investigator(s)Medicolegal Officer Or Forensic Pathologist Medicolegal Officer Or Forensic Pathologist (if necessary)(if necessary)Photographer and/or Field Evidence TechnicianLab Experts

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Processing a bodyProcessing a body

1. Obtain victim’s clothing for more thorough analysis in lab

2. Fingernail scrapings3. Hair sample4. Blood sample5. Other bio-samples6. Hand swab (for GSR)

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Forensic PathologistsForensic Pathologists

• Perform autopsies and diagnose circumstances surrounding the cause and manner of death

• Determine whether death was• Accidental• Suicidal• Homicidal

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MEDICOLEGAL OFFICERMEDICOLEGAL OFFICER’’S S RESPONSIBILITIESRESPONSIBILITIES

Identify the deceasedEstablish the TOD and DODDetermine a medical COD —the injury or disease that resulted in the person dyingDetermine the MEOD—the physiological reason that the person diedClassify the MOD

NaturalAccidentalSuicideHomicideUndetermined

Notify the next of kin

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AUTOPSY AUTOPSY anatomical pathologyanatomical pathology

Rembrandt 1632

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Autopsy ExaminationAutopsy Examination

• Autopsy means to look at oneself• Necropsy means to look at the dead• Autopsies have been practiced since

the middle ages• Term autopsy generally used in

Philippines

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Purposes of AutopsyPurposes of Autopsy1. determine or confirm the cause of death2. improve the diagnosis of a specific disease3. advance medical and scientific knowledge4. aid in the evaluation of new techniques,

procedure or medications5. help clinicians avoid repeating errors in

diagnosis and therapy in future cases6. aid in medical education7. may absolve guilt and remove concern about

possible genetic defects.

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Autopsy Under the Philippine Autopsy Under the Philippine SystemSystem

• MEDICOLEGAL AUTOPSIES

• NON-MEDICOLEGAL AUTOPSIES OR HOSPITAL CASES

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Autopsy ProcessAutopsy Process

• Incisions created in chest, abdomen and head

• Removal of organs from those areas of the body

• Y or T-shaped incision is typically used, because it facilitates examination of tongue and neck

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Autopsy ProcessAutopsy Process

• Brain is removed via incision from behind one ear to behind other ear

• Scalp is pulled upward and backward• Skull is sawed circularly or in a

tonsorial manner• Brain may be dissected immediately, or

placed in formaldehyde to preserve tissue for better examination

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Autopsy ProcessAutopsy Process• Other internal organs are removed and

weighed• Organs are also dissected to determine

disease or injury• In certain cases such as child abuse,

spinal injury, and subtle blunt trauma more extensive dissection and removal may be completed

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Obtaining Appropriate Obtaining Appropriate SpecimensSpecimens• Toxicology requires adequate

specimens for testing• Blood is usually taken from aorta• Bile taken from gall bladder• continued….

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Obtaining Appropriate Obtaining Appropriate SpecimensSpecimens• Blood, urine, liver, kidney and brain

used to determine presence of drugs• Blood- alcohol or Urine- drugs• Information from medical history,

witness statements, scene examination, and autopsy may be used to search for other drugs or poisons

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Microscopic ExaminationMicroscopic Examination

• Small portions of organs are put into a solution of formaldehyde to preserve them for study

• Diseased or injured sections of tissue are taken, as is normal tissue

• Tissue is encased in paraffin and mounted on slides with H&E dye for examination under light microscope

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DNA AnalysisDNA Analysis

• Preserve one specimen of tissue for DNA analysis

• If tissue sits in formaldehyde for too long, DNA becomes hydrolyzed and unsuitable for study

• DNA embedded in paraffin blocks or cut into sections and made into slides will not further decompose

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DNA CollectionDNA Collection

• Methods to accomplish this:– Blood spotted on absorbent paper

allowed to dry then stored in envelope– Pull head hairs, including bulbs, and

place in envelope– Cut hair has mitochondrial DNA, bulbs

include nuclear DNA

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PhotographyPhotography

• Both film and digital photography are both used, depending on law enforcement jurisdiction

• Multiple photographs must be taken

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JFK - AUTOPSY

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Che - AUTOPSY

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AutopsyAutopsy

Y incision

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DEATHDEATH•Complete

•Irreversible

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DEATHDEATH

• The Organ Donation Act of 1991 (RA7170), as amended, defines death as “the irreversible cessation of circulatory and respiratory functions or the irreversible cessation of all functions of the entire brain, including the brain stem.”

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DEATHDEATH

• Cardiopulmonary Death. – there is an absence of natural respiratory

and cardiac functions and, attempts at resuscitation would not be successful in restoring those functions.

– In this case, death shall be deemed to have occurred at the time these functions ceased; or

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DEATHDEATH

• Brain Death. – there is an irreversible cessation of all

brain functions; and considering the absence of such functions, further attempts at resuscitation or continued supportive maintenance would not be successful in resorting such natural functions.

– In this case, death shall be deemed to have occurred at the time when these conditions first appeared.

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POSTMORTEM CHANGES AND POSTMORTEM CHANGES AND TIME OF DEATHTIME OF DEATH

1. ALGOR MORTIS (BODY COOLING)

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POSTMORTEM CHANGES AND POSTMORTEM CHANGES AND TIME OF DEATHTIME OF DEATH2. 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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3. LIVOR MORTIS (HYPOSTASIS, POST MORTEM LIVIDITY, POSTMORTEM SUGGILLATIONS)

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• 4. POSTMORTEM DECOMPOSITION (PUTREFACTION)

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• 5. ADIPOCERE

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• 6. MUMMIFICATION

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• 7. MACERATION

• 8. AQUEOUS HUMOUR POTASSIUM

• 9. STOMACH CONTENTS

• 10. Forensic Entomology

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

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INDIVIDUAL OBSERVATIONS USED INDIVIDUAL OBSERVATIONS USED TO ESTIMATE TIME OF DEATHTO ESTIMATE TIME OF DEATH

• When used together the following individual observations of a body may be used to estimate the time of death– body temperature– rigor mortis– livor mortis– decomposition changes– stomach contents

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Cause of Death and Manner of Cause of Death and Manner of DeathDeath• The Cause and Mechanism of DeathCause and Mechanism of Death

is the physiological incident which started the physical progression of death in the body.

• The Manner of DeathManner of Death, on the other hand, is which category the death falls into. The Manner of Death can be one of five categories: Homicide, Suicide, Natural, Accidental, or Undetermined.

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Forensic Pathology

EVIDENCE FROM WOUNDS

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COMMON TYPES OF WOUNDS

No blackening around entry; star-shaped, often with flaps directed outward

Blackening around entry; grains of powder and deposits of powder residue

None of the above characteristics appear

Firearm:Contact (muzzle against body)

Close (less than 18 inches)

Distant (18 inches or more)

CharacteristicsType of Wound

GUNSHOT WOUNDSGUNSHOT WOUNDS

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BULLET WOUNDS

•• Point of Entry and ExitPoint of Entry and Exit• Bullet is spinning as it hits the body the entry

area is usually smaller than the exit wound.• Bullet may ricochet inside the tissue &

travels a path which is not a straight line.• Powder burns - near range hits.• contusion ring (abrasion collar) around the

bullet wound usually indicates the angle and close range.

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A BULLET PENETRATING THE SKIN• When a bullet

penetrates the skin:– the skin is pressed

inward– the skin is stretched

and perforated– the skin then returns

to its original position

9-13

(Source: Barry A. J. Fisher, Techniques of Crime Scene Investigation, © 1992, reproduced with permission of copyright owner, CRC Press,Boca Raton, Florida)

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Bullet Entry wound

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Bullet Entry wound – contact range

star-shaped laceration

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Abrasion ring – contact range

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Powder tattooing:

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Powder tattooing: close range.

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Slit like Exit wound:

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No blackening around entry; star-shaped, often with flaps directed outward

Blackening around entry; grains of powder and deposits of powder residue

None of the above characteristics appear

Firearm:Contact (muzzle against body)

Close (less than 18 inches)

Distant (18 inches or more)

CharacteristicsType of Wound

GUNSHOT WOUNDSGUNSHOT WOUNDS

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Ninoy Aquino Assasination

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Ronald Reagan Assasination

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Bullet Trajectory - Murder

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• CLOSE WOUND– Petechiae– Contusion– Hematoma

• OPEN WOUND– Incised– Stab– Punctured– Laceration

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ContusionsContusions

Color changes a bruise goes through can give rough estimate of time of injury• Dark blue/purple (1-18 hours)

•Blue/brown (~1 to 2days)

•Green (~ 2 to 3 days)

•Yellow (~3 to 7 days)

Assumes person is healthy.

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BLUNT trauma:

• The blow produces a crushing effect • Resulting in contusions, abrasions,

lacerations, fractures, or rupture of vital organs.

• Red-blue contusions are always present, but this varies by the weight of the individual (obese people bruise easier than lean people).

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Contusion: 1 week. (Yellow green)

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Blunt injury- Liver rupture.

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Mark encircling neck in a horizontal plane overlying larynx or upper trachea; sometimes broken at back of neck where hand grasped ligature; abrasions and contusions of skin not usually presentAbrasions, contusions and fingernail marks on skin

Strangulation:Ligature

Manual

Commonly found on palms of hands, fingers, forearmsDefenses

Open, irregularly shaped wounds, caused by clubs, pipes, pistols and other blunt instrument wounds accompanied by bruising or bleeding

Lacerations

Can be caused by ice picks, leather punches, and screwdrivers; result in small wounds with little or no blood

Puncture

As above; manner in which knife is thrust into and pulled out of body can result in wounds of different shapes made with same knife

Stab

Cutting wound inflicted with sharp-edged instrument, wound typically narrow at ends and gaping in middle with a great deal of blood

IncisedCharacteristicsType of Wound

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STAB WOUNDS

• Slash wounds: cuts are as wide and they are long. look like superficial bullet wounds. Other types of slash wounds are called "hesitation marks" commonly found in suicide cases.

• Incision wounds: lengths greater than their depth, greater amount of subsurface tissue is exposed in an almost oval fashion.

• Puncture wound: Stab or shive wound. distinguishable by its clean-cut edges.

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Abrasion:

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AbrasionsAbrasions

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INCISED WOUNDS

• Typically bleed a lot• Are inflicted with

knives or razors• Are narrow at the

edges and gaping in the middle

(Courtesy Federal Bureau of Investigation)

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Incised WoundsIncised WoundsSlash Stab

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Laceration:

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LacerationsLacerations

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Stab wound – hilt mark.

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Laceration: Defense wound

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Defense wound – how?

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Laceration: Defense wound

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STRANGULATION

• Homicidal, suicidal, or accidental. • PM Features:

– Intensive heart congestion (enlarged heart; right side ventricle)

– venous engorgement (enlarged veins above point of injury)

– cyanosis (blue discoloration of lips and fingertips).

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Asphyxia - Strangulation

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Brain – Hemorrhages & edema

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Fat Embolism in Pulm art.

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AUTOEROTIC DEATH

• In autoerotic death cases the investigator will typically find:– a white male partially

suspended and nude– dressed in women's

clothing or undergarments– or with his penis exposed

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DROWNING • Rapid formation of mucus block - Bronchi.

– "foam cone" covering the mouth and nostrils.– "dry drowning" - edema of Larynx - no fluid

• Stages in drowning:– Surprise - Inhales water.– Holding breath - while struggling– Pink foam – exhalation of fluid. – Respiratory arrest - Pupils dilate.– Final struggle - 3-4 quick attempts to breath.

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SMOTHERING

• Obstruction of airway. If soft object e.g. pillow or blanket. No trauma.

• Injury on the inner lips. • Cyanosis may or may not.• Petechial hemorrhage on the face,

typically around the area of the eyes.

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BURN wounds

• may be caused by heat, a chemical, or electricity.

• Fire victims often are found in a "pugilistic" position with clenched fists, resembling the pose of a boxer.

• Heat generally causes the protein in the body to contract.

• Blood and lung samples are often taken for various reasons.

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Burns:

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RAPE

• Art. 266-A. Rape is committed –– 1. By a man who shall have knowledge of a

woman under any of the following circumstances:a. through force, threat or intimidation;b. when the offended party is deprived of reason

or is otherwise unconscious;c. by means of fraudulent machination or grave

abuse of authorityd. when the offended party is less than (12)

years of age or is demented.

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RAPE

• Art. 266-A. Rape is committed –– 2. By any person who, under any of the

circumstances mentioned in para (1) hereof, shall commit an act of sexual assault be inserting his penis into another person’s mouth or anal orifice, or any instrument or object, into the genital or anal orifice of another person.

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History and physical examination

• A brief description of the assault indicates areas for medical investigation and treatment; recounting the events is often frightening for the patient, and a complete description may have to be deferred until immediate needs have been met.

• The reasons for the questions and for the examination procedure are not always clear to patients; eg, the female patient may need to be told that knowing when her last menstrual period was or if she uses a contraceptive helps determine the risk of pregnancy or that information about the time of the previous coitus helps establish the validity of sperm testing.

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History and physical examination

• Because these patients have experienced coercion, enlisting their cooperation and requesting permission for the examination are important.

• Details of the pelvic examination should be described and explained as it proceeds, and the results should be reviewed with the patient. Because being examined by a physician of the opposite sex may make the patient feel anxious, a nurse or volunteer of the patient's sex should be present to give support and to corroborate the procedures.

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Female Organ

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Hymen

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Vaginal Penetration

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• The slide demonstrates one of the best positions to examine younger children. This child is sitting on the mothers lap with the mother holding her.

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Hymenal Laceration at 5 o’clock

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Female aged 8 years.Dilated hymenal

opening,bumps (3 + 9 o’clock)

and deep rounded notch posteriorly.

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4 year old: reddening, transsection at 9 o’clock

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Female aged 2 yrs.Reddening, tag,

healing fissures, gaping sphincter,

visible mucosa.

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DRUG FACILITATED SEXUAL ASSAULTS

• Rohypnol (street name Roofies), known as the drug flunitrazepam, belongs to a class of drugs called benzodiazepines– It produces a spectrum of effects including skeletal

muscle relaxation, sedation, and reductions in anxiety

• GHB. Gamma hydroxybutyrate or GHB (also known as Gamma-OH, Liquid Ecstasy, Georgia Home Boy, or Goop)– It is another central nervous system depressant

that is used to perpetrate sexual assaults

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ROHYPNOLROHYPNOL

• Drug used by sex offenders at:– parties– bars– clubs– social drinking

locations

(Courtesy Sergeant Christopher McKissick and Detective Tyler Parks, Port Orange, Florida, Police Department)

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COLLECTION OF EVIDENCE DURING COLLECTION OF EVIDENCE DURING THE MEDICAL EXAMINATION OF THE THE MEDICAL EXAMINATION OF THE RAPE VICTIMRAPE VICTIM

• Physical evidence to be collected:– vaginal swabs,– oral and anal swabs,– pubic combing,– head and pubic hair

controls, – saliva sample,– blood sample,– fingerprint scrapings,– all clothing.

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ITEMS ROUTINELY ITEMS ROUTINELY COLLECTED FROM COLLECTED FROM SUSPECTSSUSPECTS

• All clothing,• pubic hair combing,• forcibly removed head and pubic hair

controls,• saliva and blood samples.

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FORENSIC SEROLOGYFORENSIC SEROLOGY• An analysis must be performed on a stain to

determine whether or not it is actually blood. If the sample is blood, the species must then be determined.

• Conventional serological analysis analyzes the proteins, enzymes, and antigens that are found in blood.

• If the blood sample is human, it goes on to further identification and then individualization.

• Blood analysis is a comparison analysis. The victim’s blood and the suspect’s blood must be compared to the blood found at the crime scene.

• Restriction fragment length polymorphism (RFLP) DNA analysis directly analyzes certain DNA sequences found in white blood cells.

• Polymerase Chain Reaction (PCR) DNA analysis analyzes DNA sequences that have been replicated numerous times. This procedure works well with small samples of blood. It, however, cannot individualize a blood sample.

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IS THE RED STAIN BLOOD?

– Benzidine color test,

– Phenophthaleintest,

– Leukomylokitetest,

– Luminol test,– Microcrystalline

test.

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SEMINAL STAINSSEMINAL STAINS• Seminal stains found at a crime scene are collected with

cotton swab and placed in an airtight container so that they may not be contaminated.

• A spermatozoa search is a microscopic analysis where sperm cells are visually observed.

• The acid phospatase is a presumptive analysis that test for the general existence of semen.

• Anti P-30 is a quantitative and qualitative test that identifies the presence of protein P-30 (found only in human semen). This test may also serve to individualize seminal evidence.

• DNA analysis to determine if the DNA pattern extracted from a crime scene semen stain matches the DNA pattern of the suspect:– RFLP, – PCR.

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Maximum Reported Time Intervals For Sperm Recovery in Living Sexual Assault Victims

2 – 44 Hours----------------Anus

4 – 113 Hours----------------Rectum

2 – 31 Hours----------------Mouth

7.5 – 19 Days3 – 7.5 DaysCervix

14 Hours – 10 Days6 – 28 HoursVagina

Non-MotileMotile spermBody cavity

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Sources of Biological EvidenceBloodSemenSalivaUrineHairTeethBoneTissue

Source: http://www.cstl.nist.gov/biotech/strbase/ppt/intro.ppt

PerspirationVaginal secretions

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The CellThe Cell

•• Smallest unit of life

• Compose all living things

• The “nucleus” (one of many organelles) contains genetic information the cell needs to exist and reproduce

- most cells organize genetic information into chromosomes

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DNA in the Cell Nucleus

Target Region for PCRTarget Region for PCR

chromosome

cell nucleus

Double stranded DNA molecule

Individual nucleotides


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DNA Extraction

• DNA analysis begins with DNA extraction from biological evidence

• DNA extraction is:– A chemical process by which DNA is released from

cell(s)– Other cellular components are removed leaving a

pure sample of DNA in an aqueous (liquid) solution

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DNA Amplification

• After DNA extraction DNA is amplified using the Polymerase Chain Reaction (PCR)

• PCR amplification makes many copies of the DNA to allow for detection (think photocopies)

PCR

DNA strand Amplified DNA

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Gel ElectrophoresisGel Electrophoresis• Gel with different sized pores

agarose and acrylamide are common materials

• Load DNA samples into wells at top of gel

• Run electric current through the gel

• DNA moves due to negative charge

• Smaller bands run “faster”

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DNA Detection

• Amplified DNA fragments are labeled with a fluorescent tag• DNA fragments are separated by electrophoresis (electric current)• The size of the fluorescent DNA fragment is determined by a

machine which displays the information graphically.• Analysts read the graph to determine the DNA type

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DNA Analysis• Short Tandem Repeats (STRs) are short stretches of

DNA that are repeated several times at a particular location on a chromosome

• The number of repeats and, therefore, the length of the Short Tandem Repeat DNA varies from person to person

• Each individual has two different (or two equal) length repeats at the same location on a chromosome

• STR DNA testing determines the length of the STR DNA at 13 different chromosomal locations

• STR DNA testing analysis is the most commonly used forensic DNA analysis method

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CSF1PO

D5S818

D21S11

TH01

TPOX

D13S317

D7S820

D16S539 D18S51

D8S1179

D3S1358

FGAVWA

AMEL

AMEL


A listing of all lengths at each location (loci) is called a DNA

profile

13 CODIS Core STR Loci with Chromosomal Positions

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CAG CAG CAG CAG CAG

CAG CAG CAG CAG CAG CAG

(5)(6)

Father’s Type: 5, 6

CAG CAG CAG CAG

CAG CAG CAG CAG CAG CAG CAG (7)(4)

Mother’s Type: 4, 7

CAG CAG CAG CAG CAG CAG(6)CAG CAG CAG CAG (4)

Baby’s Type: 4, 6

At a single STR locus:

*(Other possibilities: 4, 5 or 5, 7 or 6, 7)

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Statistics

• The 13 STR DNA tests produce exceedingly rare DNA profiles

• A STR DNA profile might be found in 1 person out of a quadrillion (that is, a billion million) people

• A match between two DNA samples, say, a crime scene stain and the DNA of a suspect, can link a subject to a crime

• A non-match may shift the focus away from a particular suspect

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Philippine Cases - DNA

• People vs. Vallejo. 2002• People vs. Yatar, 2004• Agustin vs. CA, 2005• Herrera vs. Alba, 2005

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That’s all folks!

forensic pathology 2007(2)

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