Book summary “Crime science”: summary

Introduction

Forensic investigation combines empirical scientific methods, meticulous crime scene preservation, and advanced laboratory analysis to uncover the truth and individualize physical evidence.

Criminal investigations present a formidable challenge when you must decode silent physical clues left behind at a chaotic crime scene. Without systematic methods, vital traces vanish, evidence suffers contamination, and wrongdoers escape justice. You need a reliable framework to transform raw physical materials into undeniable proof that holds up under rigorous courtroom scrutiny. Joe Nickell explains how modern criminalistics bridges the gap between raw clues and absolute certainty. The book guides you through foundational scientific principles, specialized laboratory techniques, and rigorous protocols for handling physical evidence.

• How do investigators preserve and document a complex crime scene without losing vital data?
• What methods separate true individualization from mere class identification in trace materials?
• How do experts extract hidden fingerprints, DNA profiles, and ballistic matches from difficult surfaces?

1. Principles of Forensic Science

Forensic science relies on the empirical scientific method, which requires that knowledge comes from direct observation of a real, rule-governed world. The ultimate goal of forensic science is individualization rather than mere identification, because all objects in the universe are fundamentally unique.

Scientific Method

The scientific method in criminalistics involves a systematic three-step process:

• Study the unknown item to determine its essential characteristics
• Examine how the characteristics compare with the established properties of known items
• Assess the similarities and dissimilarities for identification purposes

While identification places an object into a restricted class, individualization demonstrates its uniqueness. This is rooted in the principle that no two things in nature, manufacture, wear, or breakage are ever exactly the same. You can use Newcomb's Rule to calculate the probability of multiple independent characteristics occurring together in evidence. An old-fashioned typewriter with 42 standard type bars and 84 standard characters produced a mathematical formula of 1/42 multiplied by 1/84 four times. This calculation resulted in a figure of 1/2,091,059,712.

The legal admissibility of scientific evidence in courts has evolved from requiring general acceptance in a scientific field to emphasizing empirical testing and peer review. The 1923 Frye v. United States landmark case established the Frye rule of general acceptance. Later, the 1993 Daubert v. Merrell Dow Pharmaceuticals Supreme Court decision replaced it by requiring that techniques be testable and subject to peer review.

History and Lab Organization

Modern toxicology was established as a distinct forensic field in the early nineteenth century through systematic studies of the detection and effects of poisons. Spanish-born Mathieu Orfila graduated in 1811 and published Traite des poisons in 1813, establishing the foundations of forensic toxicology. In the 1840 Lafarge poisoning case, Mathieu Orfila successfully demonstrated the presence of arsenic in the internal organs of the deceased husband.

Before fingerprinting, criminal identification relied on anthropometry, a complex system of precise body measurements developed by Alphonse Bertillon. In 1879 Bertillon began developing anthropometry, and bertillonage was adopted routinely in 1882. You can identify subjects using these steps:

• Tabulate the subject's height
• Record sitting height
• Measure the length of outstretched arms
• Measure the length and breadth of the head
• Measure the length of the right ear

Edmond Locard formulated Locard's Exchange Principle that a physical cross-transfer of evidence occurs whenever a criminal comes into contact with an object. In 1910 Locard established the Lyons Police Laboratory with minimal equipment. In the 1912 cosmetics trace evidence murder case, Locard scraped pink face powder debris from under a suspect's fingernails and matched its components to the victim's cosmetics.

The twentieth century brought breakthroughs in forensic serology through blood groups and in firearms examination through the comparison microscope. Karl Landsteiner discovered blood groups in 1901, and Leon Lattes used his technique on September 7, 1915, the date of Lattes's shirt bloodstain analysis. A modern crime laboratory is structured into functional sections:

• Operate a Photography Section for crime scene and studio documentation and darkroom processing
• Maintain an Evidence Storage Section with secure receiving procedures and chain of custody controls
• Use an Identification Section for fingerprinting, latent print processing, and impression casts
• Run a Chemistry Section for drug identification, toxicology, and body fluid analysis
• Conduct microscopical examinations of trace evidence in the General Examination Section
• Operate a Firearms Section equipped with a shooting room for test-firing and distance determinations
• Utilize an Instrument Section with advanced chromatography and spectroscopy equipment
• Deploy a Crime Scene Search Section to process scenes and collect evidence

Facilities maintain reference collections with 2,000 handguns in the FBI Firearms Reference Collection and 800 shoulder weapons in the same collection. You also consult 10,000 ammunition samples in the Standard Ammunition File before July 1, 1994, the date the FBI ceased property crime examinations.

2. Crime Scene Investigation

Initial responders and investigators must follow a strict sequence of preliminary actions to prevent vital information and evidence from being lost.

Charles E. O'Hara articulates Locard's Exchange Principle. The scene of a crime involves a reciprocal exchange where the criminal leaves traces on the scene and the scene imparts traces to the criminal. You must perform specific preliminary actions at the location:

• Deal with any emergency situation that is found regardless of the following guidelines
• Identify the person who reported the crime or disturbance and if possible detain the person for questioning
• Attempt to determine the perpetrator of the crime if that can be immediately determined by inquiry or direct observation
• Detain everyone who is present at the scene, including eyewitnesses and people in possession of other information
• Summon whatever assistance may be necessary for crowd control or safeguarding the area
• Secure the scene by the issuance of necessary orders and by physical isolation using rope or tape
• Separate the witnesses so that their statements are not influenced by one another
• Secure and investigate any additional crime scene, such as a place from which a body was moved or where a vehicle is discovered
• If there is no emergency, avoid rushing to the area of focus to prevent altering or destroying minute evidence
• Refrain from moving, or even touching, any object at the scene
• If assistants are available, assign each one definite duties to minimize confusion

Collection and Reconstruction

Physical evidence must be collected in adequate quantities, kept free from contamination, separately packaged, and tracked through a rigorous chain of custody.

O'Hara warns against testing whether a tool fits a tool impression on a door because it contaminates paint traces on the blade that serve as stronger evidence. Law enforcement searches are strictly regulated by the Fourth Amendment, permitting warrantless searches only under specific emergency or consent conditions. In the 1995 O.J. Simpson case, defense attorneys unsuccessfully attempted to exclude a bloody glove because detectives searched the premises before securing a formal search warrant, arguing they responded to an emergency.

Follow precise collection practices:

• Acquire adequate samples sufficient for laboratory tests, defense analyses, and future reviews
• Collect control samples of any foreign substance or background material that might have caused contamination
• Keep evidence samples from high temperatures and place them in storage as soon as possible
• Pick up trace evidence with a forceps or spatula and place in snap-top bottles or pillboxes
• Place documents and fingerprints on paper without folding in cellophane envelopes
• Surround bullets and shell cases with cotton in separate pill bottles or boxes
• Mark objects of a cubic inch or larger with the initials of the investigator using a sharp stylus or pen
• Record receipt, description, and disposition of evidence in an official storage log in ink

3. Trace Evidence and the Microscope

Trace evidence consists of minute physical items transferred between criminals, victims, and crime scenes, proving that contact leaves microscopic traces.

According to Locard's Exchange Principle, a criminal leaves behind and takes away microscopic evidence. Forensic experts use trace evidence like hair, fibers, soil, and glass to link suspects to crime scenes, though persistence depends on time. Studies show 80 percent of fibers are lost in four hours and 5 to 10 percent of fibers remain at the end of twenty-four hours.

In a nude female victim case, body fibers pointed to a specific car trunk, pubic hair combings helped identify a rapist, and fingernail scrapings provided DNA samples.

Microscopes and Hair

The simple microscope uses a single convex lens, while the compound microscope uses objective and ocular lenses. Specialized forensic instruments include the stereoscopic microscope for three-dimensional low-power viewing and the polarized light microscope for birefringent crystalline substances. Other tools are the comparison microscope for side-by-side matching of bullets or hairs, and the scanning electron microscope for magnifications up to 50,000x. Firearms expert Calvin Goddard employed the comparison microscope to refine the process of making firearms comparisons.

Human hair serves as class evidence rather than individual evidence, retaining structural features that reveal the donor's characteristics and history. Hair resists chemical decomposition and preserves its cuticle, cortex, and medulla. Laboratory examination using a transmitted-light comparison microscope considers numerous parameters like color, reflectivity, length, diameter, and root structure.

You must collect hair evidence using specific laboratory protocols:

• Collect hair evidence carefully using tweezers or forceps
• Place collected hair into bottles with snap-on tops
• Use a clean comb in rape cases to remove foreign hair from the pubic area
• Take control samples from the victim
• Remove between thirty and fifty strands from each relevant body area
• Package strands from different body areas separately and label them properly

Fibers, Soil, Glass, and Paint

Fibers offer high evidential value because manufactured and natural textiles incorporate multiple variables like twists, weaves, and dyes. Glass fragments are compared by refractive indices and densities in density-gradient tubes. Large glass or paint pieces can be matched using fracture matching like a jigsaw puzzle. Paint is evaluated by its chemical properties, color layer sequences, pyrolysis gas chromatography, and x-ray spectroscopy.

You must collect paint evidence without contaminating the layers:

• Avoid using the adhesive tape method for collecting paint specimens
• Do not scrape off paint samples because it damages the layers
• Collect paint samples by chipping down to the surface of underlying wood or metal
• Remove paint samples with a wooden implement if possible to avoid metal traces
• Employ a steel scalpel if necessary and deliver it with the samples

In a Kansas City hit-and-run, large headlight pieces recovered from the scene fit exactly with remaining pieces found in the suspect vehicle's housing.

4. Firearms and Tool Marks

Firearms examination uses the comparison microscope to match unique bullet striations and shell case markings to a specific weapon.

Television shows and characters like Columbo frequently use the incorrect term ballistics when referring to firearms examination. Ballistics is the physics of projectile motion, whereas firearms identification examines toolmarks on bullets and casings. A firearms examiner focuses on comparing physical evidence to match them to a specific weapon without needing a degree in physics.

Firearms Examination

Fired bullets carry unique individual characteristics known as striations, which are microscopic scratches and flaws created by imperfections in the gun barrel during manufacturing or use. In 1898, German chemist Paul Jeserich became an early pioneer by firing a test bullet into soft material and comparing it under a microscope to a murder bullet.

The comparison microscope is the primary instrument used by firearms examiners to compare evidence bullets and test bullets side by side. You follow a specific procedure at the microscope:

• Mount the evidence bullet and the test bullet under the microscope objectives
• Scrutinize the entire surface of the rotating bullets at relatively low magnifications to locate the most prominent group of striations on the evidence bullet
• Keep the evidence bullet stationary and rotate the test bullet to find a corresponding area with matching individual characteristics
• Rotate both bullets simultaneously to verify if similar coincidences exist on other portions
• Proceed with further examinations at higher magnifications upon finding corresponding marks

Computerized database systems assist firearms examiners by storing, sorting, and matching digital translations of markings on bullets and shell casings. The Bulletproof database can store and retrieve three hundred thousand bullets, and compare fifty-five thousand bullets in under two hours. Spent shell cases can be matched to a firearm based on distinctive markings left by mechanical parts, though they possess less probative value than bullets unless recovered directly from a crime scene.

In a Florida case, detectives linked a murder victim to suspect Robert Jerome Perkins by discovering spent 9mm brass shells stamped W.C.C. 89 at the crime scene and matching them using a metal detector and laboratory analysis. The victim Sharonda Jackson was shot twenty-three times. The stamping indicated the 1989 manufacturing year.

Residues and Tool Marks

Obliterated serial numbers on firearms can be restored by applying chemical etching agents because the metal crystals underneath the stamped characters are placed under a strain.

When an appropriate chemical solution is applied to the metal surface, the strained area of the stamped pattern dissolves faster than the surrounding metal. The steel etching solution uses 120ml of hydrochloric acid, 90gr of copper chloride, and 100ml of water.

Gunshot residue particles deposited on a shooter's hands can be collected and analyzed using specialized testing methods. Residue particles concentrate heavily in the web area between the thumb and forefinger and can remain for roughly six hours. You collect these particles using specific techniques:

• For NAA or AA testing, spray a 5 percent solution of nitric acid on the hands and swab the web areas twice using cotton-tipped plastic swabs
• Place each set of swabs into designated plastic tubes labeled left back, right back, left palm, right palm, and control
• For SEM/EDX testing, press adhesive double-sided cellophane tape on small aluminum discs onto the top of the webbed portion of each hand

The controversial Sacco and Vanzetti trial relied heavily on early, conflicting firearms testimony. Nicola Sacco and Bartolomeo Vanzetti were convicted of a shoe factory payroll robbery and murder in Massachusetts involving sixteen thousand dollars at Slater and Morrill Shoe Factory. In 1927, Colonel Calvin Goddard reviewed the case using a comparison microscope and a helixometer from the Bureau of Forensic Ballistics to conclusively demonstrate that a fatal bullet and shell casing matched Sacco's Colt automatic. Sacco and Vanzetti were executed in 1927, and a later panel of experts reexamined the evidence and confirmed the match in 1961.

5. Fingerprints and Impressions

Friction ridge patterns provide permanent personal identification, while advanced processing methods recover latent prints from diverse surfaces.

Johannes Purkinje first classified nine fingerprint patterns in 1823. Francis Galton established permanence and classification methods, which Edward Henry later refined into a workable filing system implemented in England and Wales in 1901. Lee Harvey Oswald, James Earl Ray, and Sirhan Sirhan were all identified through latent fingerprints left at historic crime scenes. At Leavenworth Penitentiary in 1903, Will West and William West were found to have nearly identical measurements and photographs under bertillonage. Joe Nickell later published his findings on the West twins in 1980.

The Henry system divides friction ridge patterns into arches, loops, and whorls. Arches represent approximately 5 percent of patterns, loops comprise 60 percent, and whorls account for 35 percent. Al Capone's fingerprint classification formula resulted in a 1/1 primary designation due to a total absence of whorl-type patterns. Automated Fingerprint Identification Systems digitize and compare ridge characteristics at high speeds against massive databases. A Los Angeles serial killer terrorizing the city with fifteen murders was identified in about twenty minutes using an AFIS file containing 1.7 million fingerprint cards.

• Record rolled impressions of each finger from side to side on a standard card
• Record plain impressions of the four fingers of each hand pressed simultaneously followed by unrolled thumbs
• Block out prints by placing letters or symbols corresponding to pattern types below each rolled impression
• Write ridge counts of all loop patterns in the upper right corners of their blocks
• Perform a ridge trace on whorl-type patterns and write the appropriate symbol I, M, or O

Examiners establish individualization by comparing minutiae such as ridge endings and bifurcations between a known print and a questioned latent print. In an Israel burglary case, a suspect who wore socks over his hands to avoid leaving fingerprints was caught because he left bare footprints at the scene.

• Verify likeness of pattern type between both prints
• Verify qualitative likeness of ridge characteristics such as terminations and bifurcations
• Verify quantitative likeness by ensuring a sufficient number of matching ridge details are present
• Verify likeness of location by checking that ridge details share the same relative directions, distances, and intervening ridges

Latent print processing follows a non-destructive sequence. Aileen Wuornos pawned items belonging to her first victim, Richard Mallory, and placed her right thumbprint on the pawn receipt, which eventually led to her identification and arrest across 7 total murders.

• Conduct an initial visual search using a flashlight at an acute angle
• Apply laser or forensic light sources to cause latent residue to fluoresce
• Use cyanoacrylate fuming in an airtight tank for nonporous surfaces
• Apply fingerprint powders or magnetic powders with a Magna Brush if needed
• Photograph the developed print before attempting to lift it with transparent tape
• Treat porous surfaces like paper and cardboard with ninhydrin or DFO instead of powders

Impression Analysis

Tools, fabrics, shoes, and tires leave distinct physical marks that you can match through careful casting, lifting, and comparative micrography.

Cloth and leather gloves leave distinctive impressions contaminated with grease, dirt, oils, and sweat. In an English case, pigskin gloves found in a suspect's possession were successfully matched to latent impressions left at a theft scene.

• Search for glove prints using a flashlight, laser, or other light source
• Develop prints with sparing use of fingerprint powder
• Take the object with the print to the lab instead of lifting it, if possible, for direct comparison
• Make comparison prints on glass or the same material as the crime scene using similar grip and pressure

Faint fabric or dust impressions on colored surfaces require specialized recovery methods. In Nome, Alaska, a completely invisible shoe print left in blood at a double homicide was developed using luminol and matched to a suspect. During the O.J. Simpson murder trial, the prosecution used bloody shoe prints to link Simpson to rare size-twelve Bruno Magli shoes.

• Place a special plastic lifting film over the imprint
• Charge the film using a power supply so dust or powder is attracted to it
• Photograph the resulting lift for preservation, as the attachment to the film is not permanent

Moldable substances require proper casting techniques.

• Photograph the impression from directly above to avoid distortion
• Spray the impression surface carefully with shellac or clear acrylic lacquer or Snow Print Wax for snow
• Apply two coats of the proper preservative with sufficient drying time between applications
• Place a retaining frame with a depth of two inches around the impression
• Carefully pour in the casting material

Tools create microscopic striations or indentations that require careful laboratory handling. Arthur Koehler matched four nail holes in an attic floor joist and plane marks from Hauptmann's garage tool to the kidnap ladder used in the 1932 Lindbergh baby abduction involving a $50,000 ransom.

• Avoid placing a suspected tool directly against a tool mark for size evaluation to prevent destroying evidence
• Submit the actual tool to the crime laboratory for examination
• Make a series of test marks on a lead plate applying the tool at varying angles and pressures

6. Documents and Handwriting

Early writing instruction relies on imitation and copybooks, creating shared class characteristics. Later, automatic execution modified by education and personal habits produces unique individual characteristics. A single handwriting specimen can contain 500 to 1000 individual characteristics.

Handwriting comparison and document analysis reveal forgeries through individual writing characteristics and physical alterations.

You must compare questioned writing against authentic known standards that are contemporaneous and stylistically similar. Paycheck endorsements were discovered to have been signed not by the payee but by his wife when she went shopping.

• Ensure standards are as similar as possible to the questioned writing in style and instrument
• Obtain standards that are relatively contemporaneous to the questioned writing
• Verify that standards are authentic
• Use dictation rather than copying for request standards to prevent deliberate disguise
• Repeat request material several times

Document Examination

Form refers to letter shapes, proportions, slants, retraces, and connections. Line quality reflects pen pressure, shading, and speed. Arrangement covers spacing, alignment, margins, and formatting.

Forgers reproduce handwriting or signatures through tracing, freehand copying, or mechanical placement methods. A forger produced excellent fake Robert Frost manuscript poems but omitted the personal inscriptions Frost invariably penned below them. A disputed will case involving the W.M. Rice estate had a valuation of $6 million and involved forged signatures.

Macroscopic examination using reflected, oblique, and transmitted light reveals fundamental errors and watermarks. A will dated 1912 was proven a forgery because its watermark showed a letter B that had fallen off the manufacturing roller between 1917 and 1918. Stereoscopic microscopes provide a three-dimensional view to detect patching, pen lifts, and tremor. Spectral techniques such as ultraviolet light and infrared radiation reveal invisible alterations and hidden writing. The presence of optical brighteners in the Hitler Diaries indicated they were not genuine because such whitening agents were not used prior to the 1950s.

Destructive chemical tests like thin-layer chromatography identify ink formulations by separating extracted pigments. The International Ink Library houses 7,000 specimens for reference comparisons.

• Punch very tiny plugs from the inked areas in question
• Extract the ink by means of a solvent
• Spot the dissolved ink onto a silica-gel chromogram sheet
• Place the sheet in a developing tank for an interval of time
• Allow the sheet to dry and compare the resulting chromatographs with standard inks

Mark Hofmann committed murders and forged rare historical documents to cover up a high-stakes fraud. On October 15, 1985, pipe bombs exploded in Salt Lake City killing two people.

7. Serology and DNA Analysis

Forensic serology studies biological evidence such as blood and semen. You utilize initial presumptive screening tests that react to peroxidase enzymes before conducting confirmatory analysis.

Preliminary tests react to the peroxidase enzyme in blood and serve as screening tools rather than conclusive proof. Because substances like horseradish can cause false positives, you term them presumptive tests and require further confirmation.

The Kastle-Meyer color test mixes phenolphthalein reagent with hydrogen peroxide and a suspected bloodstain, producing a deep pink color for a positive reaction. Approximately 39 percent of the general population has blood type A, while 43 percent has blood type O.

• First identify a suspect substance using a presumptive or screening test for blood or semen
• Proceed to confirm the substance as blood and determine its animal or human origin using the precipitin test
• Classify the human blood according to blood grouping systems using specific antisera

Karl Landsteiner discovered that red blood cells contain specific antigens and serum contains antibodies that cause clumping. This established the ABO blood typing system, which categorizes blood into types A, B, AB, or O. About 80 percent or more of people secrete their blood-type antigens into body fluids like saliva and perspiration, classifying them as secretors.

Dr. Leon Lattes developed a procedure in 1915 to apply ABO testing to dried bloodstains on cloth and other materials by restoring them to a liquid state using a saline solution.

DNA Profiling

Alec Jeffreys discovered in 1985 that portions of human DNA structure are unique to each individual. This created the forensic breakthrough known as DNA fingerprinting.

DNA exists in all nuclei-containing cells and consists of a double helix structure with three billion base pairs of guanine, adenine, thymine, and cytosine. It can be extracted from blood, semen, skin beneath fingernails, hair roots, and saliva.

In 1986, a teenage kitchen porter became the first accused murderer cleared by DNA fingerprinting after DNA tests showed he was innocent of two rape-murders in the English Midlands. In 1987, Robert Melias became the first individual convicted of a crime based on DNA evidence in England.

Forensic science utilizes restriction fragment length polymorphism, which offers high individualization power, and polymerase chain reaction, which handles extremely tiny samples down to a billionth of a gram. The FBI's computerized national network called the Combined DNA Index System compiles state DNA databases from violent offenders and successfully links unsolved sexual assault cases across jurisdictions.

8. Forensic Chemistry and Toxicology

Chemistry serves as a fundamental forensic discipline. Its analytical aspect, chemical analysis, is split into qualitative analysis for identifying compounds and quantitative analysis for determining exact proportions.

Chemical and toxicological analyses identify controlled substances, volatile accelerants, and explosive residues in criminal investigations.

Forensic chemists divide controlled substances into four major types: narcotics, depressants, stimulants, and hallucinogens. Identification begins with field spot tests and microscopic analysis, followed by confirmatory tests.

• Use spot tests with chemical reagents for initial screening where a color change indicates a positive reaction
• Perform confirmatory tests such as infrared spectrophotometry or gas chromatography-mass spectrometry to unequivocally identify components

Toxicology involves analyzing biological samples like blood, urine, and tissues for alcohol, drugs, and poisons. Modern toxicologists test biological fluids using chromatographic methods and immunoassays. You must collect specific quantities and types of body tissues and fluids systematically for analysis.

• Obtain 10 to 20 ml of blood using a medically approved manner with a nonalcoholic cleaner and an appropriate anticoagulant and preservative
• Collect about 25 ml of urine after the subject voids the bladder and waits twenty minutes
• Collect autopsy samples including three ounces of blood without preservative, all stomach contents, half of the liver, both kidneys, all urine, and half of the brain

Arson and Explosives

Arson investigations require collecting physical evidence in vapor-tight containers to prevent the evaporation and loss of volatile liquid accelerants. Because petroleum products like gasoline are volatile, using permeable containers causes vapor loss.

• Package arson evidence only in clean vapor-tight containers such as screw-cap glass jars, metal cans, or unused paint cans with tight-fitting lids

Explosives are classified into low and high categories based on their detonation velocity. Low explosives yield a low-velocity energy wave and a low-frequency sound, whereas high explosives reach velocities up to twenty-five thousand feet per second. Laboratories analyze recovered debris using microscopic examination, thin-layer chromatography, high-performance liquid chromatography, and infrared spectrophotometry.

• Perform a microscopic examination to locate unconsumed explosive particles
• Extract soluble explosives using acetone followed by thin-layer chromatography or high-performance liquid chromatography

On February 26, 1993, a bomb made of 1,500 pounds of urea nitrate in a Ryder rental van exploded in the World Trade Center basement while 1,600 cars sat in the garage. Investigators matched a vehicle identification number on a frame rail to a rented van, recovered chemical precursor evidence from a storage locker, and matched DNA from an envelope flap to a suspect. This led to the arrest and conviction of Mohammed Salameh, Nidal Ayyad, Mahmud Abouhalima, and Ahmad Ajaj, who were each sentenced to 240 years in prison.

9. Death Investigations and Anthropology

Medical-legal autopsies, time of death estimations, and skeletal examinations reconstruct the cause and manner of suspicious fatalities.

Autopsies and Cause of Death

You determine the approximate time of death by observing postmortem changes. Body temperature drops an average of one and one-half degrees Fahrenheit per hour from a normal human body temperature of 98.6 degrees Fahrenheit. Postmortem lividity typically appears after 2 hours. Rigor mortis can set in anywhere from 15 minutes to 15 hours, with 5 to 6 hours being average, and disappears within 36 hours.

Normajean Mortenson, known as Marilyn Monroe, was found dead in her bed on August 5, 1962, surrounded by empty and partially empty drug containers, with her hand resting on the telephone and her bedroom door locked from the inside. Dr. Thomas Noguchi's autopsy revealed 8.0 mg. percent of chloral hydrate in her blood and 13.0 mg. percent of pentobarbital in her liver.

Skeletal Remains

You recover human skeletal remains through careful procedures. William Maples worked on a case involving thousands of fragments of charred bone from two human bodies and a dog sent in a single vinyl body bag.

For exhumations, you must secure specific documentation:

• A court order legally permitting the exhumation
• The exact location of the burial including cemetery address, person in charge, and plot number
• The date and time of the exhumation
• A complete list of persons attending the exhumation
• Scaled sketches of the gravesite
• Photographs of the burial site, the coffin in situ, and the coffin above ground

10 Key Ideas

1. Forensic science relies on the empirical scientific method, which requires that knowledge comes from direct observation of a real, rule-governed world.
2. The ultimate goal of forensic science is individualization rather than mere identification, because all objects in the universe are fundamentally unique.
3. Edmond Locard formulated Locard's Exchange Principle that a physical cross-transfer of evidence occurs whenever a criminal comes into contact with an object.
4. Initial responders and investigators must follow a strict sequence of preliminary actions to prevent vital information and evidence from being lost.
5. Specialized forensic instruments include the stereoscopic microscope for three-dimensional low-power viewing and the polarized light microscope for birefringent crystalline substances.
6. Firearms examination uses the comparison microscope to match unique bullet striations and shell case markings to a specific weapon.
7. Friction ridge patterns provide permanent personal identification, while advanced processing methods recover latent prints from diverse surfaces.
8. Handwriting comparison and document analysis reveal forgeries through individual writing characteristics and physical alterations.
9. Alec Jeffreys discovered in 1985 that portions of human DNA structure are unique to each individual, creating the forensic breakthrough known as DNA fingerprinting.
10. Medical-legal autopsies, time of death estimations, and skeletal examinations reconstruct the cause and manner of suspicious fatalities.