1. Dental and Tool Mark Impressions Notes

2. Dental Impressions
Forensic Science: Fundamentals & Investigations, Chapter 15
Occasionally a perpetrator will leave behind a bite mark—considered individual evidence
Why is it considered individual evidence?
Note differences in the size of teeth and jaws, position, fillings, crowns, caps, breakage, and crowding

3. Development of Teeth
Forensic Science: Fundamentals & Investigations, Chapter 15

4. Dental Patterns in Forensics
The investigation consists of recognizing, documenting, collecting, and analyzing evidence
What are the two basic ways dental patterns can be used in forensic investigations?
To identify remains
Profiling for unique bite patterns etc
There are 76 points of comparison when comparing a suspect’s dental patterns with bite marks left at a crime scene
What is the common method used to reveal whether there is a match?
1. Dental records
Forensic Science: Fundamentals & Investigations, Chapter 15

5. Human Dentition
Your teeth are unique. Forensic odontologists can use the features of a person’s teeth to match bite marks found on an object or skin to a suspect. What kind of evidence is this?

6. The Most Famous Bite – Ted Bundy
Source:

7. Introduction
Tool mark—any impression, abrasion, or cut made when contact occurs between a tool and an object
An example of physical evidence
Is it class or individual?
Even mass-produced tools have minor differences
The impressions can link the tool to a crime scene and potentially to the owner
Would it be able to convict someone on just the tool?

8. Tools and Crime Scenes Tools:
increase our ability to handle manual tasks, but
can also be used in crimes
How can a tool used in a crime lead investigators to the criminal?
Why is ownership of a tool used in a crime circumstantial evidence?
Forensic Science: Fundamentals & Investigations, Chapter 16

9. Tool Mark Impressions Indentation Marks
Result when a tool is pressed against a softer surface
Tools usually leave distinctive marks
The hardness of a tool influences the resulting marks left in the softer object
May indicate the size of the tool used in a crime
Forensic Science: Fundamentals & Investigations, Chapter 16

10. Tool Mark Impressions Abrasion Marks
An object’s surface can be ground or worn away by a tool
The harder object causes abrasions on the softer surface
Indentation and abrasion marks sometimes occur at the same time
Forensic Science: Fundamentals & Investigations, Chapter 16

11. Tool Mark Impressions Cutting Marks
Edged instruments can penetrate a softer object and separate it into parts
Cut marks are produced along the edge as a surface is cut
Forensic Science: Fundamentals & Investigations, Chapter 16

12. Tool Mark Examination
Some experts specialize in tool mark investigations
Evidence can include:
tool marks at the scene
the tool if left behind
Forensic Science: Fundamentals & Investigations, Chapter 16

13. Documenting the Evidence
Collect tool mark evidence when possible
Photograph the evidence with a measuring device to show scale
Measure the size of the impression
Why are these important?
Forensic Science: Fundamentals & Investigations, Chapter 16

14. Documenting the Evidence
Castings preserve tool mark impressions
silicone or rubber-based casting materials
Cast impressions retain the unique indentation marks made by a specific tool
Forensic Science: Fundamentals & Investigations, Chapter 16

15. Documenting the Evidence
Dust for fingerprints before applying casting material
Use magnetic dusting powder and silicone material
The size of the impression should be measured and recorded.
Forensic Science: Fundamentals & Investigations, Chapter 16

16. Collecting and Preserving a Sample
Correctly label evidence
What things need to be included on the evidence for it to be properly labeled?
Describe how to correctly pack evidence based on size, type etc in relation to tool evidence.
Record—who, where, when, and why
Maintain the chain of custody
Forensic Science: Fundamentals & Investigations, Chapter 16

17. Analyzing Tool Mark Evidence
Laboratory tool mark analysis identifies:
major characteristics defining the type of tool used in a crime
unique characteristics that might distinguish between the same kinds of tools
Forensic comparison microscopes examine tool mark characteristics that match a suspect tool
Forensic Science: Fundamentals & Investigations, Chapter 16

18. New Technology in Tool Mark Identification
Courts now require more than visual pattern comparisons
Tool mark databases (with images acquired by forensic comparison microscopes)
Algorithms to statistically analyze tool mark patterns
Scanning tools measure the depth or height of tool marks
Forensic Science: Fundamentals & Investigations, Chapter 16

19. Tool Mark Evidence in the Courtroom
The tool mark witness prepares a written report to present to a jury.
When available, provide:
Original evidence
Castings
Magnified images of tool mark comparisons
Such evidence may link a series of crimes
Forensic Science: Fundamentals & Investigations, Chapter 16

20. Summary
Write a brief Summary in your notes about what you learned through these notes. Must be at least 4 complete sentences.
Forensic Science: Fundamentals & Investigations, Chapter 16

21. Ted Bundy Case Study Questions
Answer in complete Sentences.
1. What was the murder weapon?
2. Often criminals have a characteristic that repeats itself at each crime. What was Ted Bundy’s?
3. What evidence was found at the crime scene? Label it biological or physical. Did it link Ted Bundy to the case? Why or why not
4. Where was Lisa Levy bitten? Why was this information important?
5. How did Ted Bundy usually lure his victims?
6. Why is it important to take photographs at a crime scene? How did that help Ted Bundy to be convicted?
7. Dr. Lowell Levine testified. What kind of witness was he?
8. What reasons might keep a bite mark from proving guilt? (List at least 3).