Podcast
Questions and Answers
What type of fingerprint is immediately visible to the naked eye?
What type of fingerprint is immediately visible to the naked eye?
Which method is NOT used to recover fingerprints on hard surfaces?
Which method is NOT used to recover fingerprints on hard surfaces?
What is the purpose of applying black powder when recovering fingerprints?
What is the purpose of applying black powder when recovering fingerprints?
Which technique is used to recover fingerprints from oily or wax-covered surfaces?
Which technique is used to recover fingerprints from oily or wax-covered surfaces?
Signup and view all the answers
What is used to seal and protect a fingerprint after it has been lifted?
What is used to seal and protect a fingerprint after it has been lifted?
Signup and view all the answers
What is the primary purpose of collecting and preserving a sample in forensic investigations?
What is the primary purpose of collecting and preserving a sample in forensic investigations?
Signup and view all the answers
What distinguishes major characteristics from unique characteristics in tool mark analysis?
What distinguishes major characteristics from unique characteristics in tool mark analysis?
Signup and view all the answers
What role do tool mark databases play in forensic analysis?
What role do tool mark databases play in forensic analysis?
Signup and view all the answers
When presenting tool mark evidence in court, which of the following is NOT typically included?
When presenting tool mark evidence in court, which of the following is NOT typically included?
Signup and view all the answers
What is the correct procedure for packaging small objects as evidence?
What is the correct procedure for packaging small objects as evidence?
Signup and view all the answers
Who was the first to note that the arrangement of skin ridges is unique to each person?
Who was the first to note that the arrangement of skin ridges is unique to each person?
Signup and view all the answers
Which year did Sir Francis Galton and Sir Edmund Richard Henry develop the fingerprint classification system still used in the US?
Which year did Sir Francis Galton and Sir Edmund Richard Henry develop the fingerprint classification system still used in the US?
Signup and view all the answers
What was the purpose of Alphonse Bertillon's system created in 1883?
What was the purpose of Alphonse Bertillon's system created in 1883?
Signup and view all the answers
What significant case highlighted the uniqueness of fingerprints despite identical measurements?
What significant case highlighted the uniqueness of fingerprints despite identical measurements?
Signup and view all the answers
Who was the first to implement a fingerprint classification system in the US?
Who was the first to implement a fingerprint classification system in the US?
Signup and view all the answers
Which of these years marks the first practical use of fingerprints to prevent forgery?
Which of these years marks the first practical use of fingerprints to prevent forgery?
Signup and view all the answers
What year did the records of the FBI and Leavenworth Penitentiary merge?
What year did the records of the FBI and Leavenworth Penitentiary merge?
Signup and view all the answers
Which aspect of fingerprints was noted by Sir William Herschel in 1856?
Which aspect of fingerprints was noted by Sir William Herschel in 1856?
Signup and view all the answers
What year were blood typing proteins discovered?
What year were blood typing proteins discovered?
Signup and view all the answers
What is the percentage of the population in the United States that has the RH factor protein?
What is the percentage of the population in the United States that has the RH factor protein?
Signup and view all the answers
Which type of evidence does blood typing produce?
Which type of evidence does blood typing produce?
Signup and view all the answers
What does the probability of a blood type depend on?
What does the probability of a blood type depend on?
Signup and view all the answers
What role do antibodies play in the blood?
What role do antibodies play in the blood?
Signup and view all the answers
What is true about polymorphic proteins in blood typing?
What is true about polymorphic proteins in blood typing?
Signup and view all the answers
Enzymes found in blood serve what purpose?
Enzymes found in blood serve what purpose?
Signup and view all the answers
How can knowing additional proteins and enzymes in a blood sample be beneficial?
How can knowing additional proteins and enzymes in a blood sample be beneficial?
Signup and view all the answers
What is one advantage of capillary electrophoresis over traditional gel electrophoresis?
What is one advantage of capillary electrophoresis over traditional gel electrophoresis?
Signup and view all the answers
Which of the following is NOT a use of DNA fingerprinting?
Which of the following is NOT a use of DNA fingerprinting?
Signup and view all the answers
What is the primary function of the Combined DNA Index System (CODIS)?
What is the primary function of the Combined DNA Index System (CODIS)?
Signup and view all the answers
How do local, state, and national tiers of CODIS differ?
How do local, state, and national tiers of CODIS differ?
Signup and view all the answers
What fact regarding the Innocence Project is highlighted in the content?
What fact regarding the Innocence Project is highlighted in the content?
Signup and view all the answers
What does laser fluorescence in capillary electrophoresis do?
What does laser fluorescence in capillary electrophoresis do?
Signup and view all the answers
Which of the following statements about the CODIS database is true?
Which of the following statements about the CODIS database is true?
Signup and view all the answers
What is one limitation of gel electrophoresis mentioned?
What is one limitation of gel electrophoresis mentioned?
Signup and view all the answers
Study Notes
Collecting and Preserving Evidence
- Properly document all evidence, including who found it, where it was found, when it was found, and why it was found.
- Package evidence correctly, using small containers or plastic bags for small objects, cartons or boxes for large objects, and wrapping small objects in clean paper before placing them in containers.
- Maintain the chain of custody of evidence.
Analyzing Tool Mark Evidence
- Tool mark analysis identifies the type of tool used in a crime and can distinguish between similar tools.
- Forensic comparison microscopes are used to examine tool mark characteristics.
New Technology in Tool Mark Identification
- Courts now require more than visual pattern comparisons to identify tools.
- Modern techniques include:
- Tool mark image databases.
- Algorithms to statistically analyze tool mark patterns.
- Scanning tools to measure tool mark depth.
Tool Mark Evidence in the Courtroom
- A tool mark witness should write a report for presentation to a jury.
- If available, the report should include:
- Original evidence.
- Castings of tool marks.
- Magnified image of tool mark comparisons.
Summary of Tool Mark Evidence
- Tools have unique major and minor characteristics on their surfaces.
- Tool marks can be indentations, abrasions, or cut marks.
- Tool mark evidence can be used to:
- Link a tool to a crime scene.
- Ultimately identify the tool's owner.
- Tool mark evidence must be photographed, documented, and collected or cast.
Fingerprints
Historical Development
- The earliest known records documenting fingerprints date back to 3rd century B.C. in China.
- Ancient Babylonians (1792-1750 B.C.) utilized fingerprints on clay tablets to mark contracts.
- Dr. Nehemiah (1684) described the patterns on human hands, acknowledging the presence of ridges.
- Johann Mayer (1788) was the first to note that the arrangement of skin ridges is unique to each individual.
- Jan Evangelist Purkyn (1823) described nine fingerprint patterns.
- Sir William Herschel (1856) began collecting fingerprints, realizing they were not altered by age.
- Alphonse Bertillon (1883) created a system to identify repeat offenders.
- Sir Francis Galton and Sir Edmund Richard Henry (1888) developed the fingerprint classification system still in use today in the US.
- Iván (Juan) Vucetich (1891) collected all ten fingerprints and noted measurements for identification purposes.
- Sir Henry, with two colleagues, (1896) created a system to classify fingerprints into groups; all ten fingerprints were imprinted on a card (called a ten card) for classification.
History of Fingerprinting
- Alphonse Bertillon devised the anthropometry system (1883) to identify criminals.
- The anthropometry system used body measurements, descriptions of physical appearance, and descriptions of markings on the body for identification.
- The anthropometry system failed when two people, Will West and William West, appeared to be identical twins.
- However, their fingerprints were unique proving that even twins have different fingerprints.
- The first practical use of fingerprints (1858) occurred with illiterate Indians to prevent forgery on legal documents.
- Sir Francis Galton developed the first fingerprint classification system.
- The Galton system was first used in the United States (1901) by the New York City Civil Service Commission.
- The Galton system was implemented at New York State Prison System and at Leavenworth Penitentiary (1903).
- Major city police departments adopted the Galton system after 1903.
- In 1924, the FBI and Leavenworth Penitentiary records were merged and relocated to Washington D.C.
Methods for Developing Fingerprints
- Latent fingerprints are not visible to the naked eye.
- Patent fingerprints are visible to the naked eye.
- Plastic fingerprints are impressions in soft materials like clay, tar, or wet paint.
Methods for Developing Fingerprints
- Various techniques are needed to visualize latent fingerprints:
- Powders are used on smooth surfaces.
- Chemicals are used for soft and porous surfaces.
Methods for Developing Fingerprints
- Recovery from hard surfaces:
- Black powder is used on white or light-colored surfaces.
- Gray powder is used on dark-colored surfaces, mirrors, and polished metal surfaces.
- Fluorescent powder glows under ultraviolet light.
- Carbon/charcoal and aluminum powders are used with a fiberglass or camel’s hair brush.
- Magnetic-sensitive powders can be spread with a magnet.
- After dusting, a print should be photographed and then lifted from the surface using a hinge lifter.
Methods for Developing Fingerprints
- Small particle reagent (SPR) is used to recover fingerprints on oily or wax-covered surfaces.
Methods for Developing Fingerprints
- Recovery from soft surfaces:
- Iodine fuming
- Ninhydrin
- Silver nitrate
- Super Glue fuming
Fingerprint Forensic FAQs
- Latent fingerprints are collected by comparing the bands in each sample lane to a ladder, which helps determine the STR type for each sample.
Analyzing the STR by Electrophoresis
- Gel electrophoresis is a slow, difficult-to-automate, and potentially dangerous process.
Analyzing the STR by Electrophoresis
- Capillary electrophoresis offers several advantages over gel electrophoresis:
- Capillary electrophoresis allows greater heating.
- Higher voltage used in capillary electrophoresis means molecules migrate faster.
- It produces high-speed and high-resolution separations of extremely small samples.
- Uses laser fluorescence: fluorescent dye attached to the PCR primer that amplifies the STR region of interest.
Analysis of DNA Fingerprints and Applications
- DNA fingerprinting offers numerous applications:
- Match crime scene DNA with a suspect.
- Determine maternity, paternity, or a match to another relative.
- Eliminate suspects.
- Free falsely imprisoned individuals.
- Identify human remains.
CODIS
- The Combined DNA Index System (CODIS) was created in 1994 with passage of the DNA Identification Act.
- CODIS contains a national database of DNA profiles for individuals convicted of sexual and violent crimes.
- In 2004, CODIS assisted with over 20,000 investigations.
CODIS
- CODIS is comprised of three tiers:
- Local: Labs maintain a local DNA index
- State: Combines profiles from all local labs.
- National: Compares profiles from all state systems.
CODIS
- All fifty states maintain databases for sexual offenders and convicted murderers.
- Forty-nine states include violent felons in their databases.
- Forty-three states include all felons in their databases.
CODIS
- Usage of CODIS:
- The computer compares submitted DNA profiles with profiles stored in the network.
- If a match is found in the Convicted Offender Index, the lab receives the perpetrator’s identity.
- If a match is found in the Forensic Index, it suggests a link between two crimes.
- Labs must verify any discovered matches and law enforcement can then pool resources to solve the crimes.
Interpretation of DNA Profiles
- It is easier to exclude a person from suspicion using DNA than it is to prove that they are the only suspect.
- The Innocence Project reports that three times more suspects are proven innocent by DNA analysis than are proven guilty.
Cellular Components of Blood
Blood Typing—Proteins
- Blood typing was discovered by Karl Landsteiner in 1900.
- It identifies the presence or absence of protein embedded in blood cells.
- It is quicker and less expensive than DNA profiling.
- While it produces class evidence, it can link suspects to crime scenes or exclude suspects.
Blood Typing—Proteins
- Blood Type distribution in the US population:
- Type A: 42%
- Type B: 12%
- Type AB: 3%
- Type O: 43%
Rh Factor
- 85% of the population has a protein called Rh factor on their blood cells.
Blood Typing—Antibodies
- Antibodies are secreted by white blood cells, are Y-shaped proteins, and attach to antigens to destroy them.
- Antigens are foreign molecules or cells that react with antibodies.
Blood Enzymes
- Enzymes are complex proteins that catalyze biochemical reactions.
- Many enzymes and proteins in the blood are useful for identification.
Blood Typing — Probability and Blood Types
- The probability of a blood type is calculated by multiplying the probabilities for each protein group.
- Blood Type A+ has a probability of .42 x .85 (Type A 42 %, Rh Factor 85%) which equals .357 or 35.7%.
- Identifying additional proteins and enzymes in a blood sample provides a more precise match.
Tests for the Presence of Blood
- Other blood typing systems rely on the presence of proteins in red blood cells.
- Polymorphic proteins have multiple forms, can be identified, and their statistical occurrence in the population can be calculated.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the essential concepts of collecting and preserving evidence related to tool mark analysis in forensic science. It highlights the importance of proper documentation, packaging, and the latest technologies used in identifying tool marks. Test your knowledge on courtroom applications of tool mark evidence and the procedures involved.
