Question: Why is it almost impossible to obscure

> What evidence do investigators look for when trying to determine whether a suspect has fired a handgun? Where is such evidence typically found and why?

> How is shot pattern used to make a distance determination for shotgun blasts? What factors other than distance to target can affect the distance determination?

> A criminalist studying a dyed sample hair notices that the dyed color ends about 1.5 centimeters from the tip of the hair. Approximately how many weeks before the examination was the hair dyed? Explain your answer.

> List three class characteristics of a gun barrel.

> How did the comparison microscope make possible modern firearms examination?

> Briefly describe how a comparison microscope works and what it is used for.

> Why might an examiner choose a microscope with a lesser magnification to study a specimen?

> What does numerical aperture (N.A.) measure? What is the difference between a lens with N.A. 1.0 and one with N.A. 0.5?

> What is the difference between a real image and a virtual image?

> How does one calculate the magnification power of a compound microscope?

> What is vertical illumination and under what conditions would a forensic scientist use it to examine a sample? Why is it superior to transmitted illumination under such conditions?

> Why does a compound microscope produce greater magnification than a magnifying glass? How does the eyepiece lens contribute to magnification?

> How can a scanning electron microscope be used to determine whether a suspect has recently fired a gun?

> Indicate the phase of growth of each of the following hairs: a. The root is club shaped b. The hair has a follicular tag c. The root bulb is flame shaped d. The root is elongated

> How can a scanning electron microscope be used to identify the elements present in a specimen?

> What is the basic difference between a scanning electron microscope and the other microscopes used in the crime laboratory?

> Explain how the infrared micro-spectrophotometer determines the identity of a specimen. What type of physical evidence is the micro-spectrophotometer typically used to analyze?

> What is the main advantage of the micro-spectrophotometer?

> What happens to a light beam that passes through a polarizing crystal? What happens when plane-polarized light passes through a second polarizing crystal set perpendicular to the first crystal?

> What is the most widely used microscope in the crime laboratory? What features make it particularly suited for examination of physical evidence?

> List two unique characteristics of the stereoscopic microscope.

> How does a magnifying glass enlarge objects viewed through it?

> Which module is responsible for saving all of the raw data produced by feature extraction and putting it into a simple and easy to read format for the system?

> What biometric system process or module performs most of the “heavy lifting” for the system?

> The accompanying figure depicts stress marks on the edge of a glass fracture caused by the application of force. If this is a radial fracture, from which side of the glass (left or right) was the force applied? From which side was force applied if it is

> What is the first process that each biometric system must perform? What does it consist of?

> What are some of the specific stages that comprise gait recognition as a form of behavioral biometrics?

> What is the most commonly used type of behavioral biometrics?

> Which category of biometrics is more concerned with the way a human performs an action, rather than focusing on a specific physiological trait?

> Which type of scans are the least accurate form of forensic biometrics currently available in the physiological category?

> What is RISC? Why is RISC particularly beneficial for law enforcement officers?

> What are the two primary types of forensic biometrics?

> What is NPPS? What possible outcome(s) may result with the addition of NPPS to the NGI?

> Which system within the NGI has a criminal database containing 30 million front-facing mugshot photos of individuals with tenprints on file?

> What are the three most widely accepted techniques used to create a viable reconstruction and analysis of a human face?

> Indicate the order in which the bullet holes were made in the glass depicted in the accompanying figure. Explain the reason for your answer.

> What is the Eigenface technique?

> What is one significant advantage of automated facial recognition, as compared to other forms of biometrics such as iris and fingerprint systems?

> The NIR wavelength band is located within what nm range of the electromagnetic spectrum?

> What are some of the reasons why iris biometrics is replacing retina biometrics?

> What is one of the main problems with retina biometrics?

> When did the first documented attempt to identify someone using the iris occur? Who was responsible for this attempt?

> At which stage of pregnancy does the iris began to form?

> What are the two main functions of biometrics?

> What is the final step in fingerprint identification? Why is this step necessary if a computerized database of fingerprints is available to the forensic scientist?

> Briefly describe how the Automated Fingerprint Identification System (AFIS) creates a fingerprint image. What characteristics of the fingerprint does the AFIS record for comparison?

> An accident investigator arrives at the scene of a hit-and- run collision. The driver who remained at the scene reports that the windshield or a side window of the car that struck him shattered on impact. The investigator searches the accident site and c

> What aspect of a fingerprint forms the basis for primary classification under the FBI system? What is the main drawback of the FBI system?

> Describe each of the three classes of fingerprints. Which class is the most common in the population? Which is least common?

> What is the dermal papillae and why is it important in fingerprinting?

> What aspect of a fingerprint determines its individuality?

> What major advance in fingerprint technology was pioneered by Juan Vucetich and Sir Richard Henry? What was the importance of this advance?

> What is digital imaging and how is it used in fingerprint analysis? What is the greatest limitation to digital imaging?

> When should a fingerprint be “lifted” from a crime scene? Describe how to lift and preserve a fingerprint using adhesive tape.

> What phenomenon underlies many of the new chemical techniques used to visualize latent fingerprints? Why is this phenomenon so valuable in fingerprint visualization?

> What is the most commonly used chemical method to visualize latent fingerprints on porous materials? If this method is unsuccessful, what other technique typically is used?

> Gunshot residue patterns (A) through (D) (contact, 1 inch, 6 inches, and 18 inches) from a 40-caliber pistol are shown in the figures. Match the firing distance to each pattern.

> List two types of specialized fingerprint powders and name one advantage each has over traditional fingerprint powder.

> List and describe the three types of fingerprints that may be found at a crime scene.

> Who published the first book on the science of fingerprinting? What were the book’s most important contributions to understanding fingerprints?

> Distinguish between a homicide and a suicide.

> List the five categories of the manner of death.

> Describe important factors in characterizing a gunshot wound.

> Describe the characteristics of a sharp force injury.

> Describe the characteristics of a blunt force injury

> A primary objective of the autopsy is to determine the cause of death. Define cause of death.

> Describe what’s entailed in an internal examination during an autopsy.

> How would you go about collecting impressions in each of the following situations? a. You discover a shoe print in dry dirt. b. You discover a tool mark on a windowsill. c. You discover tire marks in soft earth. d. You discover a shoe print on a loose pi

> Describe what’s entailed in an external examination during an autopsy.

> List the areas of the skeleton that can be used to determine the gender of skeletal remains.

> What important considerations must be made when determining PMI using forensic entomology?

> Describe the approach for estimating the time of death by measuring potassium levels in the ocular fluid.

> Immediately following death, a chemical change known as rigor mortis occurs. Describe this phenomenon.

> Another condition arising after death is livor mortis. What does this entail?

> After death the body undergoes a process known as algor mortis. What is this?

> List items to be collected and sent to the forensic laboratory from an autopsy.

> What is the drawback effect? How is it helpful to an investigator?

> Name three factors that affect the amount of backward spatter produced by a gunshot wound.

> Criminalist Ben Baldanza is collecting evidence from the scene of a shooting. After locating the revolver suspected of firing the shots, Ben picks the gun up by the grip, unloads it, and places the ammunition in an envelope. He then attaches an identific

> Define the terms area of convergence and area of origin and explain what kind of information each reveals to an investigator.

> In general, as both the force and velocity of impact increase, what happens to the diameter of the resulting blood droplets?

> What is the difference between forward spatter and back spatter? Which is more likely to be deposited on the object or person creating the impact?

> What is the difference between the shape of a bloodstain that impacts a surface at a low angle and one that impacts at a higher angle?

> How can an investigator tell the direction of travel of blood from the shape of a bloodstain?

> Which of the following is of paramount importance in the interpretation of bloodstain patterns? a. The direction of impact b. The surface texture c. The angle of impact d. The amount of blood

> Name and describe two methods for documenting bloodstain patterns.

> Explain how the shape of stains in a trail pattern can help investigators determine the direction and speed at which a person was moving.

> How can pools of blood aid in reconstructing a crime scene?

> What is a flow pattern? What should one surmise if a flow found on an object or body does not appear consistent with the direction of gravity?

> You are investigating a shooting involving a 12-gauge shotgun with a moderately high choke. The spread of the pattern made by the pellets measures 12 inches. In your opinion, which of the following is probably closest to the distance from the target to t

> How does the first transfer pattern in a series differ from subsequent ones?

> What is a transfer pattern? How is a simple transfer pattern created?

> What is a void pattern? How might a void pattern be useful to investigators?

> What is expirated blood? Name two ways to distinguish expirated blood from other types of bloodstains.

> What determines the size of blood drops in a cast-off pattern? Explain.

> What is crime scene reconstruction?

> Why are some jurists wary of allowing unconditional use of scientific evidence in court?

> What is the value of class evidence? Why is this important in making a case to a jury?

> What is the greatest weakness of class evidence? List two factors that contribute to this weakness.

> Define the product rule and explain how it can be used to determine whether two blood samples come from the same source.