Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Warm-Up September 26, 2014 How are hair and fiber analysis used to solve crimes?

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Objective SWBAT describe, compare, and identify the different types of fingerprints.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Agenda 1.Atlanta Child Murders Documentary 2.Hair & Fiber Analysis Lab 3.Physiology of Fingerprints 4.Types of Fingerprints 5.Print Cards 6.Ridges 7.Ridges Activity 8.ID Fingerprint Challenge 9.Forensic Files Friday 10.Exit Slip

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Atlanta Child Murders Documentary 26. What did the medical examiner say had changed once Wayne Williams had been arrested? 27. What was the murder that some people think suggests that the fiber evidence could be faulty? 28. Why did they close the case on the child murder victims and not have a trial? 29. What happened to Robert Henry that caused him to change his statement about seeing Wayne Williams with a victim? 30. What did the DNA testing from the FBI suggest? 31. What did Williams say about his supposed CIA training?

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Hair & Fiber Analysis Lab Some changes made… –Complete Suspect Comparison –Answer the Post Lab Questions when you are finished

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. What are Fingerprints? If a finger touches a surface, perspiration and oils from the body are transferred onto the surface, leaving an impression of the finger’s friction ridge patterns. Fingerprints may contain traces of any material found in perspiration including DNA and chemicals such as nicotine.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. What are Fingerprints? Friction ridges are found on skin in the following regions: –Palms of hands –Palmar aspect (palm-side) of fingers –Soles of feet –Solar aspect (sole-side) of toes They exist to give firmer grip and resistance to slippage. The number of ridges and their shape is largely determined by genes.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Skin Surface Outer surface layer of skin is the epidermis. The inner layer of skin is the dermis. Between these two are the dermal papillae. The papillary pattern determines the form and pattern of the friction ridges on skin surface.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Skin Surface Each skin ridge is populated by a single row of pores that are openings for ducts leading from the sweat glands. Perspiration is released and deposited on the surface of the skin through these pores.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Fingerprints are Unique Dermatoglyphics is the study of fingerprints. No two fingers have yet been found to have identical ridge characteristics (minutiae). Ridge pattern remains unchanged throughout life.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Fingerprints do not Change Friction ridge pattern of skin develops in utero (before birth) due to uneven stresses in the different layers of the developing skin. Identical (monozygous) twins –have the same DNA. –have different fingerprints.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Intentionally Altering Fingerprints Very difficult to do, but there has never been a lack of trying. –Bank robber John Dillinger attempted to burn off his fingerprints with corrosive acid. They grew back. –Illegal immigrants and criminals sometimes undergo finger print plastic surgery. They can still be identified by palm prints and DNA. To change the pattern requires obliteration of the dermal papillae (1- 2 mm deep). Attempts to destroy the pattern can backfire and cause more unique details!

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Types of Fingerprint Patterns There are 3 basic fingerprint patterns –loops (60-65% of population) –whorls (30-35%) –arches (5%)

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Loops Have ridges entering from one side of the print, turning, and leaving from the same side. The pattern area of the loop is surrounded by two diverging ridges known as type lines. The approximate center is called the core. The ridge point nearest the type line divergence is known as the delta (capital greek letter Δ).

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Loops 65% of the population have loops. All loops must have one delta. If the loop opens toward the little finger then it is a ulnar loop. If the loop opens towards the thumb then it is a radial loop.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Arches In an arch, ridges enter from one side of the print and exit on the opposite side.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Arches Arches are divided into two distinct groups: –plain arches –tetrarches or tented arches The tetrarch consists of an upthrusted ridge in the center of the arch.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Whorls All whorl patterns must have a core and at least two deltas

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Special Loops The double loop is made up of two loops combined into one fingerprint. The pocked loop has a small circle at the core.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Other Patterns An accidental pattern contains two or more patterns, but not the plain arch, and is not covered by other categories. It may consist of a combination loop and plain whorl or loop and tented arch.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Forensic Files Friday

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Homework Read Chapter 14, pgs

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved. Exit Slip September 26, Get out a mobile device or use one of the computers and go to m.socrative.com. You can also use one of the iPads that has the Socrative app. 2. When prompted, enter for the room number. QUESTION: How are fingerprints classified and identified as individual evidence?