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Pick a Category

Hair Analysis

Blood Typing

Suspect Identity

Finger-Prints

DNA Mystery

Hair Analyzed

Blood Antigens

Hair Com-parison

Finger-printing

Disappearing Dimes

Face Re-cognition

Finger-print

DNA

Type

Blood

Fingerprint Identification

Fingerprint identification can be used because:

• A. Fingerprints have ridges

• B. Fingerprints are unique

• C. Fingerprints can always be seen

• D. Fingerprints always point to the guilty person

Blood Identification

Knowledge of composition of blood:

a. Only helps to determine is human or animal

b. Shows that there are only about 8 pints of blood in the human body

c. Can help to determine a suspect

d. None of the above

Blood Type

Which of the following is most true:

a. Blood cells have two antigens

b. Blood typing uses the ABO System

c. Both

d. Neither

Face Recognition

Hair Comparison

Hair can be used to identify a person because:

A. Different races have hair of different types

B. All hair has the same basic characteristics

C. Age can be determined from a follicle of hair

D. Human hair can be easily recognized from animal hair

DNA

DNA is used to determine a suspect because:

a. All DNA is totally and completely unique

b. DNA at a crime scene is usually hard to find

c. DNA can be matched to a suspect

d. The same DNA can be narrowed down to a group of people

Fingerprint Data• fingerprint is an impression of the friction ridges on all parts of the finger.[1] A friction

ridge is a raised portion of the epidermis on the palmar (palm) or digits (fingers and toes) or plantar (sole) skin, consisting of one or more connected ridge units of friction ridge skin.[1] These are sometimes known as "epidermal ridges" which are caused by the underlying interface between the dermal papillae of the dermis and the interpapillary (rete) pegs of the epidermis. These epidermal ridges serve to amplify vibrations triggered when fingertips brush across an uneven surface, better transmitting the signals to sensory nerves involved in fine texture perception.[2] The ridges do not assist in gripping objects, sometimes in fact reducing grip to as much as 30% compared to completely smooth fingerpads.[3]

• Fingerprints may be deposited in natural secretions from the eccrine glands present in friction ridge skin (secretions consisting primarily of water) or they may be made by ink or other contaminants transferred from the peaks of friction skin ridges to a relatively smooth surface such as a fingerprint card.[4] The term fingerprint normally refers to impressions transferred from the pad on the last joint of fingers and thumbs, though fingerprint cards also typically record portions of lower joint areas of the fingers (which are also used to make identifications).

• Facts:• The patterns of ridges on our finger pads are unique: no two individuals—even

identical twins—have fingerprints that are exactly alike.• We leave impressions—or prints—of these patterns on everything we touch with any

pressure.• The prints can be visible, as when our fingers are dirty or oily, or they can be latent,

as when they are made only by the sweat that is always present on our finger ridges.• Injuries such as burns or scrapes will not change the ridge structure: when new skin

grows in, the same pattern will come back.• Dactyloscopy is the practice of using fingerprints to identify someone.

Fingerprint Science

• Fingerprint identification is sometimes referred to as:

• A. Forensic identification

• B. Dactyloscopy

• C. Palmer location

• D. Plasticoscopy

Hair to Analyze

Hair that is taken for analysis is usually taken from:

a. The temples

b. Top of the head

c. From the arms

d. From the nape of the neck

Hair Analysis• The scientific study of hair is called trichology and this field dates to the mid 1800s.

Forensic scientists perform three major types of hair analysis. Chemical assays are used to assess the use of illegal drugs, to screen for the presence of heavy metals in the body, and to test for nutritional deficiencies. The root of the hair has cells that contain DNA, which can be used for DNA analyses. Microscopic comparison of hair collected from two different places is used to determine if the hairs are from the same person or animal.

• Because hair can be moved from location to location by physical contact, the presence of a specific person's hair can link a suspect or a victim to a crime scene. If hair is transferred directly from the region of the body from which it originates, it is considered a primary transfer. Approximately 100 head hairs are lost per person per day. These hairs usually end up on clothing, furniture, or on other items in the environment. Transfer of hair from these items is called secondary transfer. Secondary transfer of hair is very common with animal hairs, which are commonly found on pet owners and in the environment of pet owners and can be used to link suspects to crime scenes.

• Hair grows out of living cells in epidermis of mammals. It is almost entirely made up of the protein keratin. The club-shaped hair root is anchored in a follicle, which has associated muscles, called arrector pili. When these muscles contract, hair becomes oriented nearly perpendicular to the skin. The hair itself is composed of three layers: the medulla, the cortex, and the cuticle. The medulla is the innermost canal that extends through the hair. In humans it can be continuous or discontinuous, interrupted by a series of empty spaces. Surrounding the medulla is the cortex, which makes up the majority of the mass of the hair. The outermost layer is the cuticle, which is a single layer of scales. In humans these scales overlap quite a bit and cling tightly to the cortex.

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Hair Analysis Continued• A variety of factors influence the microscopic analysis of hair, including the experience and

technique of the examiner. Because microscopic hair analysis is subjective, no statistics can be assigned to the probability that a hair belongs to an individual. The analogy often referred to is that an individual can recognize the face of a friend among a group of people even though all of them have the same features: eyes, nose, and mouth. In the same way, an experienced hair examiner can recognize those features of hair that determine whether or not it belongs to a specific individual.

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Hair Analysis Continued• Pigments are found in both the cortex and the medulla, but they are absent from the

cuticle. In humans, the pigments tend to be distributed toward the outer edges of the cortex, but this can vary depending on ethnicity. In human hair, the medulla is generally narrow, taking up less than a third of the diameter of the entire shaft. In hairs from animals, the diameter of the medulla is larger than half the diameter of the entire shaft. The cross section of human hair is most often circular, but occasionally oval.

• Using morphologic features, forensic scientists classify six different types of hair on the human body: head hair, eyebrow and eyelash hair, beard and moustache hair, body hair, pubic hair, and axillary hair. Biochemical studies show that there are no significant differences in chemical structure among the hair types. Animals also produce different types of hair. They often have coarse guard hair external to softer fur hairs. They also produce whiskers and longer hairs in such places as the tail and mane.

• In humans, hair undergoes cyclical phases of growth (anagen), transition (catagen), and resting (telogen). During the growth phase, the cells of the follicle actively divide and grow upward. The average anagen phase lasts about 1,000 days. During the telogen phase, the cells of the follicle are dormant and hairs naturally fall out. This phase usually lasts for 100 days. At any time, between 10 and 18% of all the hairs on a human head are in the telogen phase; about 2% are in the catagen phase and the rest, between 80 and 90% are actively growing. There is no pattern to determine which hairs on the head are in any phase at a given time.

• Because hair grows out of follicles in the skin, materials in the body are incorporated into the hair. Hair grows relatively slowly, so it takes several weeks for materials in the body to be reflected in the composition of the hair. Hair that is collected for the presence of drugs, heavy metals, and nutritional insufficiencies is usually clipped from the nape of the neck. About a spoonful is necessary for analysis.

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Hair Analysis Continued• Results from hair composition analysis are somewhat controversial. A variety of factors impact

the results, including the location on the body from where the hair was removed, the color of the hair, and the person's age and race. Standards vary as to methods of washing, cutting, and collecting hair. Standards for analysis also vary and a single lab may report different results from subsamples of the same sample. False-positives for illegal drugs are not uncommon and can occur when someone is in the presence of second hand smoke from marijuana or crack cocaine. External substances such as air pollution, composition of the water used to wash hair, and materials used to treat hair such as shampoo, hairspray, and hair dyes may also skew results. Hair analyses that do report the presence of illegal drugs or heavy metals should be verified with blood or urine tests.

• Microscopic hair analysis has two components. The first is to identify characteristic features of the hair in question. The second is to then compare these features in the questioned hair and hair from a known origin. In particular, the hair in question may be collected as evidence from a crime scene and the known hair may be collected from a suspect or from a suspect's possessions. Microscopic hair comparison in forensic laboratories usually involves the use of two compound microscopes that are optically connected so that the hair in question and the hair from a known origin are in the same field of view. The hair is usually magnified between 40x and 400x.

• The first step of the examination involves verifying whether the hair in question is that of a human or an animal. If the hair is from an animal, the examiner can potentially identify the species from which it originated, but it is usually impossible to assign the identity of a hair to a particular animal. In the case of dogs, most examiners can attribute hairs to given breeds. If the hair is from a human, the examiner will determine the part of the body from which it originated. Some of the features that the examiner uses include length, shape, size, color, stiffness, curliness, pigmentation, and the appearance of the medulla. The majority of hairs examined in forensic investigations originate from the head and the pubic areas.

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Hair Analysis Continued• Microscopic hair examiners can categorize hair into three different racial groups based on

established models. These groups are European ancestry, Asian ancestry, and African ancestry. Hairs from people of European ancestry are generally straight or wavy, have cross-sections that are round or oval and have fine to medium-sized pigment granules that are distributed evenly. Hairs from people of Asian ancestry are straight, have circular cross-sections and have medium-sized pigment granules that are grouped in patches. They may also have a thicker cuticle than in the hairs of other races. Hairs from people of African ancestry are usually curly or kinky and they have an oval cross-section. The pigment granules are large and are found clumped in groups. The hair shaft may twist or buckle and commonly splits. Head hair shows the most distinguishing characteristics for determining race, however other body hairs also evidence identifying characteristics. Complications with the assignment of race involve analysis of hair from infants and from people of mixed race.

• The determination of age from hair is usually not possible by microscopic examination. Some general information may be surmised however, as the hair of infants is usually fine and contains few racial indicators. Hair of the elderly shows signs of pigment loss and often has variable diameter. The follicle of hairs contains chromosomes that can be stained to determine the sex of the individual. However, sex is usually determined from DNA testing.

• Examination of the root can provide information as to the nature of a crime, especially if violence is suspected. If hairs fall out naturally during the telogen (resting) phase, the root will have a club shape. If hair is pulled out with force, the root will be stretched or broken and may have tissue attached. Examiners can also determine if hair has been burned, cut, or crushed.

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Nina had expected her great-great uncle's house to be like mansions in the movies, with marble columns and rose gardens, not peeling paint and a weed- filled lawn. But Dad explained that Waldo hated spending money, except on his collections. Nina's parents thought the kids were playing outside. Instead, they snuck into the candlelit parlor. "Your Mom will freak out if she catches us," Nina's cousin Max muttered. "I know. But Uncle Waldo traveled a lot and I never got to meet him while he was alive. I just want to see what he looks like." "At least turn on some lights," Max grumbled. "This is creepy." "Didn't you hear the lawyer talking to Mom and Dad? Uncle Waldo called the parlor his 'candle room.' He never had it wired for electricity." She crept over to the coffin and peered inside. Waldo wore a tuxedo with a ruffled shirt and red cummerbund. His white hair was neatly combed, his nails manicured, and his diamond stickpin and silver cufflinks glittered in the candlelight. "He looks nice," Nina whispered. Max took one glance inside, then pulled Nina away from the coffin. "Weird," he said. "I didn't think people wore tuxedos when they were buried." "He liked it. Dad said Uncle Waldo even had his portrait painted wearing this exact same outfit. He put it in his will that he wanted to be dressed for his funeral exactly the way he is in that portrait." Max shivered. "I wonder who had to dress him?" "Harvey, Waldo's assistant." "Like a butler?" "Sort of." "So he really was rich. Hey, your Dad was kidding about inheriting twenty cents, right?" Nina led her cousin back down the hall. "Well, Waldo did leave Dad two dimes. But Mercury is facing the wrong way or something, and that makes them worth a lot of money. Mom said it was enough to pay my way through college someday." "Cool." "Uncle Waldo's daughter, Fiona, inherited the house and all this stuff." They entered the study where Nina's parents were talking to the lawyer, Mr. Baxter. Max gawked at Waldo's "collections." Display cases everywhere were filled with jewel-encrusted objects. Harvey, Waldo's assistant, handed glasses of lemonade to the kids, then left. Nina thought he looked as sour as the drink tasted. "Fiona arrived earlier, but you probably won't see her until the funeral tomorrow," the lawyer was saying. "Waldo requested burial near his gazebo. Harvey will dig the grave himself." "Poor Harvey," Dad murmured. Baxter nodded. "At least Waldo set up a trust that will continue to pay Harvey's salary, small as it is. Now, would you like to see the dimes?" In the master bedroom upstairs, the lawyer twirled the combination lock on a wall safe while Nina studied the painting of Waldo that hung above the fireplace. Decked out in his tux, ruffled shirt, jade cufflinks and diamond stickpin, he seemed to wink down at her. Baxter removed a box from the safe and opened it. Everyone gasped. The box was empty. "Impossible!" the older man exclaimed. "They were here an hour ago." "The safe isn't damaged," Mom remarked. "How many people know the combination?". He frowned. "Just myself, Fiona and Harvey. I'd better call the police." "Go ahead," Dad said. "But no matter who stole the dimes, they're small enough to be hidden anywhere. Even if the police tear the house apart, I'll bet they never find them." Nina stood up, staring at the portrait. "I think I know who took the dimes," she whispered to Max. "And if I'm right, I know where they are."

Dime Suspects

• Baxter

• Fiona

• Harvey

Correct!!!

"When I peeked into the coffin, I noticed that Uncle Waldo's cufflinks were silver, because they were shining in the candlelight," Nina said to Max. "Now take a good look at the portrait." Max examined the painting and began to smile. "Everyone follow us, please," Nina announced. "The mystery is solved.

Downstairs in the parlor, Nina explained. "Why would Mr. Baxter have even told Dad about the dimes if he had stolen them? And Fiona's already inheriting a lot of money. But Mr. Baxter said Harvey wasn't paid much" "So where are the dimes?" Max asked. "Right here." Nina pointed at the coffin. "In the painting, Waldo's cufflinks are green, but I remembered that he was wearing silver ones." No one said a word about her sneaking in to see Waldo. Dad peeled a dime loose, rubbing glue off Mercury's profile. "Harvey would have retrieved them before he buried the coffin," said Baxter. "Clever." "Not as clever as Nina," Mom said, hugging her.

Blood Evidence• Frequently, the forensic analysis of a crime or accident scene will

involve the analysis of blood. Whether in the form of fresh liquid, dried blood, jelly-like coagulated blood, or patchy drops or stains, blood can be a treasure trove of information. As one example, the pattern of a bloodstain can tell a forensic investigator much about the nature of the accident or crime. Just as important is the composition of the blood.

• A typical human body contains approximately ten pints (4.7 liters) of blood. Depending on the severity of a wound, blood can be lost slowly or, as in the case of a severed artery, can spurt quickly out of the body. A forensic examiner can tell a great deal about the nature of the accident or crime from the pattern of the blood residue. Additionally, knowledge of the composition of blood and properties of these components is also valuable in identifying a victim or implicating an assailant.

Blood Type InfoDetermining which person the bloodstain belongs to involves an

investigation of blood types. The human blood contains over 100 different antigens, therefore it would be time consuming and unpractical to test for every single one. Serologists instead use a number different blood testing techniques, but by far the most common and effective technique is the ABO system. This system is also used to determine compatibility for blood donors and recipients. The ABO blood type system involves checking the surface of the red blood cells for two antigens known as A and B, with blood type being named after the type of antigens it contains - A, B, AB and O. By noting that a blood clump forms when the same type of antigen meets the same type of antibody, an experiment can be done on the solution of blood to determine the blood type

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DNA Information• Since 1987, forensic DNA analysis has made appearances in U.S.

courtrooms. Originally known as "DNA fingerprinting," this type of analysis is now called "DNA profiling" or "DNA typing" to distinguish it from traditional skin fingerprinting.

• Although used in less than one percent of all criminal cases, DNA profiling has helped to acquit or convict suspects in many of the most violent crimes, including rape and murder.

• Every single cell in our bodies contains DNA, the genetic material that programs how cells work. 99.9 percent of human DNA is the same in everyone, meaning that only 0.1 percent of our DNA is unique!

• Each human cell contains three billion DNA base pairs. Our unique DNA, 0.1 percent of 3 billion, amounts to 3 million base pairs. This is more than enough to provide profiles that accurately identify a person. The only exception is identical twins, who share 100 percent identical DNA.

• At a crime scene, DNA is everywhere. It is present in all kinds of evidence collected at the scene, including blood, hair, skin, saliva and semen. Scientists can analyze the DNA in evidence samples to see if it matches a suspect's DNA

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