Forensic Science: 2011

Sunday, December 4, 2011

In this lab each table was given five similar clues to establish a profile of the perpetrator. Each table got one set of fingerprints, two hair or fiber samples, a torn note, and a liquid smudge on a piece of paper. We were told to analyze each piece. When analyzing we were supposed to create what kind of person would do this, what you knew, what you needed more information for, and what you didn’t know.

Witness experiment

This experiment was designed to see how well of a witness you could be. Each table had magazines and cut out heads of people in relatively the same size. Each person picked their “person” and cut out the hair, eyes, nose, and mouth. We then jumbled the pieces up in the middle and picked random parts to make a “suspect.” The “suspect” was then shown to the person to their left and they had to re-make that person after only 30 seconds of getting to look at them.

Lipstick Lab

All students put on a shade of lip gloss or lipstick in order to make our lip prints visible on a notecard. We each got a half notecard to “kiss” and make a print on. We analyzed each of our own prints to look at the distinguishing characteristics of our lips. We then put each person’s print at our table again onto a piece of paper. We then jumbled up our notecards and had another table decide whose print was whose.

Hair and Fiber Lab

In this lab, we used various types of hairs and fibers to look under the microscope and identify the differences. Some of the hairs we used were Caucasian hair, Caucasian dyed hair, African-american femal hair, African-american male hair, synthetic hair, dog hair, and cat hair. Some fibers we used were nylon, cotton, silk, and wool. We looked at each sample underneath the microscope and recorded on paper what we saw and the differences between them.

Fingerprinting Lab

We used the t-zone of our face to put oils onto our thumbs. The t-zone is the oiliest part of your face, so it makes the print more visible when powder is added. We placed it on a the table and used powder to try to make the print visible so we can lift it. We then took a piece of clear tape and lifted the print and placed it on a piece of paper. Mine did not work very well. The powder should have been finer to stick to the print better.

Poison Lab

In this lab, different stations were set up that held different poisons. Each station had three different samples of potential poisons that we had to identify by using methods such as pH testing and reagent testing. Sugar, cyanide, aspirin, metal poison, iodine, and ammonia are the poisons that we identified in the lab. With this lab, we were able to learn and understand different ways to test drugs that analysts come across in the field.

Drug Analysis

In this lab, we were given simulated drug samples that resembled real drugs and were told to identify and label them. First, we took the “drugs” and diluted them to the point where the substance was dissolved in water. Then we took a samples of the dilute, tested it with ph paper, and recorded the ph and the color that it displayed. Then we used LSD and Cocaine reagent that would show a color if the dilute was positive for the reagent. The Cocaine reagent would turn blue if the mixture was positive for Cocaine and the LSD would turn yellow if LSD was present. We tested six substances and three were positive of Cocaine while the other three were positive for LSD.

Famous Forgery Cases -Mussolini Diaries

In 1957 Amaliaand Rosa Panvini, 86 forged thirty volumes of the “diaries” of former Italian dictator, Benito Mussolini. An experts examined the diaries and thought that since such a great number diaries they were real. Eight years later the diaries were bought by the Sunday Times for $150,000 and were soon declared a fake and the women were arrested.

Footprint Analysis

In this lab, we were told to leave a footprint impression in the record the characteristics of the impression. We recorded weather information, time, date, location, and direction of the footprint. Then we wrote down properties of the (length and width) of the shoe impression that was left. We were able to determine the gender and size of the person who left the print. Males leave a deeper impression because of their size and a larger print because they usually have larger feet unlike women. With this lab, we were able to see the techniques used by analysts in recording and analyzing the suspect by their foot impression.

Check forgery activity

In class we did a little test to see if anyone could forge someone else’s signature. At our table we each had a piece of paper that had a place to write your signature, a place for someone to free-hand your signature, and a place for someone to trace your signature. We wrote the sentence “the quick brown fox jumped over the lazy dog,” in cursive and in print in the first box. We then traded our sheets with someone at our table to see if they could forge our signature.

Forgery Methods

When forging a signature, there are two ways to go about it. You can trace or you can free-hand. When tracing, a person uses the signature and focuses on making the exact same lines and dots. This method is not as accurate because the pressure and line quality are different. When free-handing the person has to practice and learn how the person signs, so there are less noticeable differences.

Handwriting History

In suicide, forgery, and kidnapping cases, handwriting analysis is very important. An Italian professor at the University of Bologna published a book in 1622 about characteristics in handwriting. The term “graphology” means the study of the way people form letters when they write. This term was created by Abbe Michon in 1870. Michon published a book analyzing penmanship and inspired Milton Bunker to create and organization named International Graphoanalysis Society. This organization is still used today to study graphology.

12 Handwriting Characteristics

1. Line quality- How dark is the line

2. Spacing of words and letters- How far away are words

3. Ratio of the relative height, width and size of letters- Is there a size difference in letters

4. Pen lifts and separations- Does the person stop writing in order to form new letters

5. Connecting strokes- Are letters or words connected

6. Beginning and ending strokes Does the person write loopy

7. Unusual letter formation- Does the person use a lot of capital letters when they write

8. Shading or pen pressure- Does the person press down hard or light when they write

9. Slant- Is there a slant when the person writes

10. Baseline habits- Does their writing begin at the top or below the line

11. Flourishes and embellishments- Does the person write fancy

12. Diacritic placement- How are the 't's crossed and 'i's dotted

Landmark cases

There was a case in 1936, in which the wife of an NBC executive was beaten to death. She was strangled with her pajama top, bound with twine, and left on the bathroom floor. A chemist was brought in to examine the crime scene. He found one hair, half an inch long, that he later identified as horse hair. The twine was able to be matched to a specific manufacturer and distributor, and proved to be delivered to a moving company that had delivered a horse-haired couch earlier that day. This allowed police to put pressure on the delivery person under suspicion, who later confessed.

In 1982, there was a victim of rape and strangulation found dead, who was abducted six days earlier. There were orange fibers found in her hair that were suspiciously like fibers found in a 12-year-old murder victim from eight months earlier in the same county. The fibers were determined to be carpet fibers of a unique color. Later a 28-year-old woman was abducted and held captive in a man’s house. She was tortured and the man seemed to have his mind set on killing her. She escaped one day and reported him to the police. It was found that he had a similar van to the one that the abduction victim was picked up in. In the van there was a unique colored orange carpet. There were only 74 yards of that carpet sent to that part of Ohio. So the murderer was convicted.

Reliability of hair and fiber

Hair and fiber analysis is reliable in the fact that it can prove someone was somewhere, but it does not help with a timeline. Hairs and fibers cannot prove when someone was in a certain place. Hair is more reliable when it has a follicle attached, which can contain DNA. Fibers can usually only be reliable when there is a source for it to be compared to.

Analysis of hairs and fibers

Hairs and fibers are analyzed similarly. Both are looked at under a microscope to determine the type. Hairs need to be determined if they are human or animal. If human, it needs to be determined what ethnicity, whether it is colored, whether it is synthetic, and if it has the follicle still attached. If the follicle is attached there might be a chance for DNA evidence. If the hair is identified as animal, it needs to be determined what kind of animal it is and what color the animal is. If the evidence is a fiber it needs to be identified as to what type of fiber it could be. Ex: wool, cotton, rayon, polyester, etc. it also needs to be determined whether or not it could is dyed. Hairs and fibers can be used to prove that a person was at a scene at some point in time. If fibers are found on a chair, it can be proved that a person wearing that fiber was sitting in that chair.

horse hair

Major fibers used today

The most common fiber is probably cotton. Cotton is often times spun into yarn to make clothes, furniture, etc. Another common fiber is polyester. Polyester is most commonly used in clothing, furniture, safety belts, and insulation for pillows and bed sheeting. Spandex is common, but when used it is usually mixed with polyester or cotton. Nylon is fairly common, being used for active wear, swimwear, hosiery, as well as parachutes, combat uniforms, and tires. Wool is a very common fiber that is obtained from sheep. Wool is most commonly used in clothing, blankets, horse rugs, etc.

cotton

Hair and fiber collection techniques

Hairs and fibers can be found under fingernails, on clothing, on car seats, etc. before touching the hair or fiber, it should be photographed. If the hair is long, like a human hair, then it can be picked up with a gloved hand. If the hair is short like an animal hair or fiber tweezers or tape should most likely be used. When the hair or fiber is picked up, it should be bagged and labeled.

Procedure for lifting/collecting fingerprints

First, a CSI should determine which surface(s) contain fingerprints. This helps in deciding how to lift them. If the fingerprint is on a non-porous surface, the best bet would be to use a powder. The color of the powder should contrast the color of the surface that contains the fingerprint. If the fingerprint is on a porous surface, the best bet would be to use super glue fumes. To do this, you heat super glue (cyanoacrylate) to around 120°F in a metal plate. You then put the heat source, metal plate, and surface containing fingerprint into an airtight container. After you have made the print visible, you should photograph it. You then take a clear piece of tape, place over the print smoothly, and remove it. Then place the print on a fingerprint card of a contrasting color to the powder.

History of Hair and Fiber Analysis

Edmond Locard was one of the first people in the world to investigate hair and fiber. In1910 he came up with the idea to establish a laboratory to investigate evidence from crime scenes. It was a few rooms in the attic above a court house in Lyon, France. In 1912 the court finally decided to recognize his laboratory in court. Locard then headed the first criminal investigation lab in the world, which got much recognition from countries everywhere. Between 1931 and 1935 Locard published seven volumes of Traité de criminastique (Treaty of Criminalistics). These books are still referred to today.

Francois Goron was one of the first people to try to use hair analysis in a case. His first case that he tried to use it, did not work out. The hair found in a dead woman’s hand could not be identified as human because the scientific world had b=not yet advanced that far. In 1899, Goron tried to use hair and fibers in another case, which was successful. He was able to prove that the perpetrator’s hair was dyed, resulting in the arrest.

Techniques/chemicals for lifting fingerprints

Let’s say that a house gets broken into. Well the perpetrator will leave prints everywhere, sometimes without knowing. He may leave prints on porous or non-porous surfaces. Examples of porous surfaces would be paper, unfinished wood, or cardboard. Non-porous surfaces could be glass, plastic, or a metal. Since we said that the house was broke into, there are likely to be fingerprints on the door knob, which in this case is going to be metal. For a porous surface, like a metal, you should most likely use a powder. A metallic, black, or white colored powder, is best depending on which powder would contrast the most with the surface containing the fingerprint. If the crime is a kidnapping, then there might be a note. The note, written on paper, would be an example of a porous surface. There are two ways you can lift prints from a porous surface. One being use a chemical or chemical solution. The most common chemicals are iodine, ninhydren, and silver nitrate. The other way would be to use super glue fumes in an airtight container.

Whorl

There are four main types of whorls: plain whorl, central pocket whorl, double loop whorl, and accidental whorl. A plain whorl has at least one ridge that makes a complete circle in the center. A central pocket whorl has at least one ridge that makes an oval, spiral, or any other variant of a circle. Double loop whorls have an “S” shape somewhere on the print. An accidental whorl consists of two separate patterns, excluding the plain arch, that do not match any other definition of a fingerprint pattern.

plain whorl central pocket loop whorl double loop whorl

accidental whorl

Loops

There are two types of loops: radial and ulnar. Radial loops are when the ridges of a fingerprint enter from the side of the finger closest to the thumb; named after the bone in your forearm that connects to your thumb (radius). In a loop fingerprint the ridges turn around and exit the same side that they entered. An ulnar loop, has the same shape but starts and exits on the side closest to the little finger and is also named after the bone in your forearm that connects to your little finger (ulna).

radial loop ulnar loop

Arches

There are two main types of arches: plain arches and tented arches. In arch fingerprints, ridges run from one side of the fingerprint to the other, without turning backwards. Plain arches move smoothly from one side of the print to the other, without any significant peaks; although they may have a wave like motion in the center. Tented arches also move smoothly from one side to the other without any back tracking; but in tented arches, there is a significant peak in the middle.

plain arches tented arches

Plastic Prints

Plastic prints are fingerprints left in a material that keeps the shape of the print. A perfect plastic print could be in clay, but criminals aren’t usually dumb enough to do that. They are commonly found in melted candle wax, putty on window panes, or thick grease deposits on a car. These are apparent to the human eye, so there is no need to lift these, they only need to be photographed.

Direct Prints

Direct prints are prints that are obvious to the naked eye. They are caused by foreign material such as flour, being placed on a surface. Generally since these fingerprints are very visible, they are only photographed, not lifted. Other materials for a transfer of a print could be dirt, blood, ink, clay, etc.

Latent prints

A latent print is one that is left by accident, whether it can be seen by the naked eye or not. A latent print might only have a part of the fingerprint, or part of the fingerprint might be smudged. It might also happen that there are overlapping fingerprints. These overlapping fingerprints could be from the same person, or more than one person. For example, a TV remote control, almost everyone in the house touches it, so there are possible overlapping fingerprints. Latenet fingerprints tend to be less reliable than other types of fingerprints.

Wednesday, November 16, 2011

History of Fingerprinting

Fingerrints have been found for thousands of years. They have been found on ancient Babylonian clay tablets, seals, and pottery. Bricks and tiles from Babylon and Rome have aslo been discovered holding fingerprints.

Most of these were deposited unintentionally in the process of making the craft. But some were also made to add decoration. Babylon had a smart idea to use fingerprints to put beside signatures to verify the identity and prevent forgery. After Babylon did this, it was like a virus, a few other countries followed their lead and started using fingerprints to verify the authenticity of documents.

Forensic Science