First of the Day….

1. First of the Day….

2. What can blind you, and make you see?

3. I can be quick and then I'm deadly, I am a rock, shell and bone medley. If I was made into a man, I'd make people dream, I gather in my millions by ocean, sea and stream.

4. Mr. Jones filed a lawsuit against the company he worked for claiming they were drugging him to make him a better worker. He claimed that the company encouraged consumption of coffee which he found contained a drug called Trimethylxanthine. Trimethylxanthine is an addictive drug that increases alertness, improves concentration, and gives you a euphoric feeling. It operates using the same mechanisms that amphetamines, cocaine, and heroin use to stimulate the brain (only to a lesser degree!) When the coffee was tested it was found that it did contain large amounts of Trimethylxanthine. But, Mr. Jones did not win his lawsuit. Why?

6. Impressions Impression evidence: objects or materials that have retained the characteristics of other objects or materials through direct contact. Footwear and tire tread impressions are the most common types of impression evidence.

8. Footwear examinations are less common than fingerprint examinations. Why? 1. Such marks are not as commonly sought or recovered by crime scene investigators. 2. Clarity of reproduction required for conclusive individualization is not as often present. 3. Individualization is only possible when random, individual characteristics have been imparted to the sole of the shoe that are reproduced in the impression. When this individual detail is present in sufficient quantity and quality, it is possible to individualize an impression to a specific shoe.

9. Tire Tread Impressions Vehicles also leave impressions at or near the crime scene. Tire tread impressions are even less common than footwear impressions. The Forensic Examiner attains the skill to visualize and enhance these types of impressions through a set of procedures. As a form of physical evidence, footwear and tire tread impressions provide an important link between the suspect and the scene of the crime.

10. Gathering Footprint Evidence

12. There are four basic methods of recording footwear impressions at the crime scene. 1. Photography 2. Documentation/Sketching 3. Casting 4. Lifting The crime scene investigator, when collecting evidence, should "use know methods in the best possible way to develop the impression to its fullest potential.“

13. Sketch and Document Tread patterns

14. Measurement

15. Why are footprint impressions important? When someone walks, runs, or drives a vehicle, over soil, impressions are made. A frame is built around the print or track, casting material is poured in and dried, and then the cast removed and photographed. As shoes and tires are used, individual characteristics such as nicks, cuts, and wear patterns develop. These characteristics may show up in prints and impressions and can be compared with a suspect's shoes or tires. It is often possible to recreate the events leading up to, those occurring during, and those occurring after the crime

16. Crime Scene Footwear Evidence Found in 2 forms: impression: three-dimensional - made in mud or other soft material print: “stamped image” on a solid surface by dust, powder, blood, mud.

17. Impressions:

18. Prints:

19. Footwear evidence, as well latent fingerprint evidence, is classified into three categories of crime scene prints: • Visible Prints • Plastic Prints • Latent Prints Visible print on forehead

20. Visible Prints: • Occur when the footwear steps into a foreign substance, is contaminated by it, and then comes in contact with a clean surface and is pressed onto that surface. It is visible to the naked eye. • Most common are left on a contrasting surface, such as a kitchen floor, with blood, grease, oil, or water • This type of print must be photographed, prior to any other methods being used. An electrostatic dust lifter can also be utilized when the evidence is in dust.

21. Plastic Prints: occur when the footwear steps into a soft surface, such as deep mud, snow, wet sand, or dirt creating a three-dimensional impression. This type of impression should be photographed and then cast. These impressions are three-dimensional; they allow examiner to see length, width, and depth.

22. Latent Prints “invisible” The most overlooked print and are generally found on smooth surfaces. They can be developed the same way latent fingerprints are. This type of print needs a variety of powders, chemicals and even forensic light sources to make it visible in order to properly be collected. In most cases these prints should also be photographed prior to any recovery process.

23. PRESERVING FOOTWEAR ANDIMPRESSIONS Footwear prints and impressions should be photographed: • As part of the general scene • Also photograph with a scale • Dental Stone is used in casting impressions • We will use Plaster of Paris

24. Black and White Photos unless the impression is in blood, and oblique light is shone onto the footprint. It is usual to take a series of photographs, each time varying the position of the light source, and a scale should be added to the scene. If the surface is light, the print may be highlighted using aerosol paint.

25. Photographs of footwear impressions at a crime scene 1st photo: only the impressions are shown 2nd photo a ruler added to show sizes Next: casts will be made

26. 3 steps of recording footwear impressions at Crime Scenes • Photograph • Document/Sketch • Cast or Lift

28. How to make a casting 1. Make a dam or place a frame, such as a shoebox, shallow baking pan around the impression of the footprint to hold the plaster. Spray with fixing spray or hairspray

29. Pour the mixture carefully down a Spatula to fill the entire impression. Allow the cast to set for at least an hour before removing it. Comment on the characteristics of the shoe from which the impression must have been made. The impression can be compared with a shoe of the suspect, if one has been apprehended.

30. Footprint Analysis: Footprint impressions from casts and/or by photography will give investigators information about: · The number of criminals. · Points of entry and exit. · Positions of suspect(s), victim(s) and witness(es). · Direction(s) of movement/travel and pathway(s) through the crime scene. · Time period, from short-lived impressions in frost, snow, dew.

31. What about tire prints? Footwear impressions and tire impressions are examined in the same fashion. Impressions can be three-dimensional when left in snow or soft soil, or they can be two-dimensional when a dirty, bloody, or other impression is left on a hard surface. Footwear impressions can be as individual as a fingerprint.

32. There may be thousands of people that have the same shoe as you, yet your shoe impression may be unique. As you wear your shoe, the tread wears down to your individual walking style. Also, accidental scratches, nicks, and cuts are left on the bottom of your shoe. Tires undergo the exact same changes making them unique as well. 

33. Questioned impressions from crime scenes can be photographed, lifted, or cast with dental stone to compare to suspect shoes or tires. A comparison of tread designs or wear patterns can lead to positive ID.

34. Crime Scene Footprint Impression Instructions 1. Sketch the footprint(s)

35. 2. Take all measurements: Length and all width variations Make sure to measure the length and the width at the various width points

36. 3. Record condition and all observations of footprint, soil type… Note the characteristics of the shoe from which the impression must have been made. The impression can be compared with a shoe of the suspect, if one is apprehended. [Usually a dam is made by placing a frame around the footprint impression to hold the plaster/dental stone -- your technique will vary a little in this lab]

37. 4. Spray the footprint with hairspray to gently to firm up loose soil, be careful not to spray too hard and disturb the soil or blow it away.

38. 5. Mix the Plaster of Paris by gradually adding water. The ideal mixture should be pancake batter consistency – kind of runny…

39. 6. Pour the mixture carefully into your footprint, try to keep within the margins of the footprint. Fill the entire footprint.

40. 7. Allow the cast to set for at least an hour before removing it. 8. Fill out worksheet and turn it in.

41. Tomorrow you will gently clean your plaster impression I will label them, and you’ll try to ID/match them to the person who made them:

43. Shoe Cast Letter:_____ shoe type (dress, casual, athletic_____ Brand:_________ small sketch of tread male or female made print?__________ Measurement/Size:_________________

44. http://www.podia-clinic.com/forensic/index.html

45. Sargur Srihari applies pattern recognition expertise to developing computational tools that will make forensic shoe print searching more precise.

46. (PhysOrg.com) -- A shoeprint etched in blood or dust can make a crucial difference in a criminal case, but it all depends on the ability of human examiners to identify a matching shoeprint pattern from thousands in their databases. It's a laborious, inefficient task. http://www.physorg.com/

47. University at Buffalo computer scientists are developing tools to make the search-and-match process like a Google search not like hunting for a needle in a haystack with research funded by the U.S. Department of Justice. "Shoeprint evidence is some of the most widely available type of evidence at crime scenes," says project leader: SargurSrihari, Ph.D., SUNY Distinguished Professor in the UB Department of Computer Science and Engineering

48. But, like many areas in forensic science, shoeprint analysis lacks a scientific basis. "It's a process largely based on human knowledge and intuition," Srihari says.

49. Most shoeprints left by suspects are photographed or/extracted from a surface and submitted by human examiners in criminal science investigative (C.S.I.) units. Those shoeprint images are posted on Internet portals, then viewed by forensic experts around the world who attempt to locate a match from thousands of shoeprint images in existing databases.

50. Analyzing shoeprints consists simply of human experts looking at shoeprints from a crime scene," says Srihari. "There are no formal techniques that examiners can use to substantiate a 'positive' finding one way or another.