Define class characteristics and list two (2) examples. Define individual characteristics and list two (2) examples. From the following photos, discuss the class and individual characteristics.
ANSWER:
Scenario: You arrive at a breaking and entering to process the scene. The glass to the back door of the residence is broken and it appears that the suspect may have cut his thumb or finger. The suspect has taken a lap top computer that was sitting on the dining room table. No other items are missing from the residence. The suspect exited through the back door.
List and describe the 3 main types of evidentiary fingerprints that may be found at a scene? Describe the types of fingerprints may have been deposited in this scenario? What causes a fingerprint to be deposited on a surface?
ANSWER:
The three types of finger prints found at a crime scene include visible, latent, and plastic. There are two types that may have been deposited in the scenario. They include visible finger prints because of the blood, and latent finger print because of the body secretions. The major factors that cause finger print to be deposited on the on a surface include blood, secretion from the body, dirt, grease, and oil (Tilstone, Savage, & Clark, 2009).
Forensic Databases
- List the name of the database used in the following departments and the type of information that is contained in each database. (4 points)
- What is a database? How do the forensic databases work? How is a forensic database useful for casework examination? (6 points)
ANSWER:
Data can be described as a collection of data detained in a computer. Forensic data base are used to keep criminal information. In general, information is saved in the computer for future use if a suspect is caught in another crime. For instance, the database can be used to detain DNA, ink sampling, tire track or a glass (Jackson & Jackson, 2011). Forensic database is mainly used to assist investigators and scientists to carry out their research in the laboratories. There are several ways in which forensic databases are useful casework examination. Over the past 15 years, forensic database have significantly assisted in enhancing criminal justice system. For instance, information can be attained from inadequate quantities from challenging samples that that have little or no evidence (Jackson & Jackson, 2011).
Hair Examination (10 points)
Scenario: A woman is walking to her car which is parked in a parking garage. She is approached from behind. The person places his arm around her neck and is holding a sharp object against her neck. He asked for her purse. As he is trying to remove it from her arm with his other hand, she reaches back and grabs his hair. He takes off and she is unable to describe her attacker. However, she has a few of his hairs in her hand.
Describe the three morphologic components of hair. List and describe the three stages of hair growth. What can be determined from the hair evidence the victim recovered? How would you examine the hair the victim recovered?
ANSWER:
The three morphological regions of hair include cuticle, medulla, and cortex. The three stages of hair growth include anagen phase, catagen phase, and telogen phase. The hair is composed of a protein known as Keratin. Therefore, it is clear that the hair recovered has DNA because of the Keratin. The hair is examined through hair microscopy in the forensic laboratory. In general, the purpose of conducting the examination is to determine the person involved in a crime scene. The examination is determined in order to verify the person involved with the act o crime (Tilstone, Savage, & Clark, 2009).
Glass Examination (10 points)
Scenario: - A hit and run occurred, where the victim was found dead only a roadside. She was known to walk home from work and was last seen around 11pm as she left work. Approximately 11 days later a possible suspect was identified. A preliminary exam of his vehicle showed considerable damage to the top and side of the driver’s side front fender. A headlamp was missing. This was an older vehicle, which had two (2) headlamps one above the other. This is an example of how the headlamps would appear on the vehicle examined.
Exam of Suspect’s Vehicle:
- No biological evidence (blood, skin, hair) was identified on the vehicle;
- The vehicle appeared to have been washed and cleaned thoroughly;
- There were fragments of broken glass lodged in the bumper and inside the area of the missing head lamp;
- Paint samples were collected from the vehicle;
- Samples of debris from underside of vehicle were collected as an exemplar (known, standard).
Determine if there is an association between the glass fragments from the scene (where victim was found) and the fragments collected from the vehicle (bumper and area of missing head lamp). Nine fragments were recovered from the scene and ten fragments from the vehicle. It was noted that the manufacturing imprinted numbers and letters were visible in the glass fragments.
What is glass composed of? How are automobile headlights manufactured? Describe the techniques are used to compare glass fragments? Discuss the limitations of glass examinations. Describe how the glass in this case would have been examined.
ANSWER:
Glass is made of sand, soda ash, dolomite, limestone, and salt cake. Car lights are made of polycarbonate plastic. In general, the polycarbonate is lighter than glass. There are several techniques used to compare glass fragments. These techniques include ICP-MS technique and EC-ICP-MS method. Based on the scenario, the major limitation of glass examination is texture. Glasses have a smooth texture which gives lab experts a hard time. The best way to carry out glass experiment is to take the glass to the lab and use the required chemicals. Glass collected from a crime scene should be tempered with (Jackson & Jackson, 2011).
- What is the importance of the ridge characteristics (minutiae) for a fingerprint examination?
- In the following figure, identify 12 ridge characteristics:
ANSWER:
The significance of ridge characteristics is to identify a suspect. In general, finger prints have more than 100 points that can be used for identification purposes (Tilstone, Savage, & Clark, 2009).
12 ridge characteristics
- Ridge Dots
- Bifurcations
- Trifurcations
- Ending ridge
- Ridge crossing
- Spurs (hooks)
- Islands
- Bridges
- Enclosures (lakes)
- Eye
- Dot
- Delta
Paint Examination (10 points)
What is the composition of paint? List the four organic coatings used in automobile paint. How can paint evidence be examined? What is PDQ and what does it contain?
ANSWER:
Composition paint can be described as a mixture of ingredients. The four organic coatings used in automobile paint include binder, solvents, pigments, and addictives. Paint evidence can be examined from a crime scene if the paint in scratched or removed. In general, law enforcements collect samples of the paint and resemble with evidence collected. PDQ stands for Paint Data Query. PDQ restrain codes that are printed on tablets and capsules
Fiber Examination (10 points)
Describe the difference between natural and manufactured (synthetic) fibers. Give examples of natural and manufactured (synthetic) fibers. Describe the basic chemical structure of manufactured (synthetic) fibers. Discuss the examination of fibers.
ANSWER:
There are a number of differences between natural and synthetic fibers. Synthetic fibers are manmade while natural fibers are found in nature. For instance, wool, Catton, and silk are all considered to natural fibers. Synthetic fiber includes tire, shoes, and polythene bags. The following is the chemical structure of manufactured (synthetic) fiber of Nylon
Examination of fibers is mainly done to determine the type of color. It involves comparison of samples (Jackson & Jackson, 2011).
Firearms Examination (10 points)
Markings/striations left behind on a projectile/bullet and the cartridge casings may link evidence to a particular firearm. List and describe in detail the different types of markings/striations that may be left behind on a projectile/bullet and cartridge casings.
ANSWER:
Striations or markings can as parallel to longitudinal axis of a projectile or gun. There are two major types of markings that may be left behind on projectile/gun. They include ejector marks and breech face marks. Ejector marks are marks that are slightly left behind by a bullet when it hits an object. Face marks are marks that are left by a bullet in the nose of the gun after a shot. There are two different kinds of markings that are left behind on cartridge casings. These markings include firing impressions, and execrator marks. Firing impressions are formed when the firing badge of a bullet strikes the primer of middle fire magazine case of a rim fire magazine case. Execrators are marks are marks that when the bullet strikes. The marks are left scattered all over the thin air (Frith, 2007).
Tool Mark Examination (10 points)
What is considered a tool mark? How is a tool mark created? What type of crime scenes are tool marks mostly commonly found? How is tool mark evidence collected? Discuss the class and individual characteristics that may be found on a tool mark. What type of trace evidence may be found on a tool mark?
ANSWER:
Tool marks can be described as sedimentary structures that are found on the bases of particular strata that show small-scale irregularities and grooves. Anything that usually occurs at the interface of two differing lithologies or grain size can be described as a tool mark. The types of crimes scenes were tool marks are mostly found in violent crimes such murder. Tool evidence is collected in different ways. Tool marks are photographed before they are collected. The class characteristics that may be found on a tool mark include finger prints. Individual characteristics that may be found on a crime scene include hair. The major traces that may be found on a tool mark include blood samples (Brown, & Davenport, 2012).
References
Brown, R. M., & Davenport, J. S. (2012). Forensic science: Advanced investigations. Mason, OH: South-Western Cengage Learning.
Frith, A. (2007). Forensic science. Tulsa, OK: EDC.
Jackson, A. R. W., & Jackson, J. M. (2011). Forensic science. Harlow, England: Pearson/Prentice Hall.
Tilstone, W. J., Savage, K. A., & Clark, L. A. (2009). Forensic science: An encyclopedia of history, methods, and techniques. Santa Barbara, Calif: ABC-CLIO.
Yount, L. (2007). Forensic science: From fibers to fingerprints. New York: Chelsea House.
