Neff+Evidence+collecting

How to examine and handle Evidence from a Crime Scene
Information and explainations taken from: 3/1/2008 HeadJam: http://www.teachingtools.com/HeadJam/index.htm =Fiber= Like hair, fibers can indicate contact between a suspect and a crime. A fiber is the smallest unit of a textile. Some fibers occur naturally and come from plant or animal sources, such as cotton or wool. But more than half the fibers currently used in the production of textiles are man-made, such as polyester and nylon. Fibers sometimes are transferred directly, such as, from one person’s clothing to the crime scene. Or, fibers can be transferred indirectly — for example a fiber is transfered to som eone else's clothing, then later transfered to the scene of the crime. Another example a transfer is said to be indirect when a fiber from a bedspread clings to someone’s shirt and is then transferred to a second person’s clothing. If a fiber originating from a suspect matches a fiber found at a crime scene, experts must try to show that it is more than a coincidence. Fortunately for investigators, textiles today have more variety than ever. Different companies often use different processes to produce fabric. Therefore, analyzing the shape of a fiber’s cross section gives experts one way to compare various specimens. If the cross section is unusual, it can add value to the fiber as evidence. Many different dyeing processes are also used by textile producers to give fiber its color. Sometimes color is also added to the surface of fabric, such as printed fabrics. How a particular fiber is dyed and colored provides another important characteristic to examine. __**While examining the fiber, the utmost care is taken to make sure trace evidence is not lost.**__
 * Hair and Fiber Collection**
 * Such evidence is often found in fabric abrasions or caught in torn materials or other areas on hit-and-run vehicles. In some burglary cases, it may be found caught in torn screens, broken glass, or other locations.
 * Examination of fibers can normally be conducted to determine the type or color of fiber. Such examinations will sometimes indicate the type of garment or fabric from which they originated.
 * Fibers and threads can also be compared with suspects clothing to determine whether or not they could have come from this clothing.
 * Fibers can be examined as to type of fiber, natural such as wool silk and cotton or man made like polyester and nylon
 * If the fibers are short or few in number, and if it is possible to do so, wrap the area or the entire item containing the fibers in paper and send the whole exhibit to the Laboratory.

=**Fingerprints**=

Marking of Fingerprint Evidence

 * All such evidence should be marked in some distinctive manner, such as is the case with any other type of physical evidence. Precautions should be taken, when marking evidence, not to damage or destroy potential latent fingerprints.
 * Lifted, developed latents should also be marked or sealed in marked envelopes.
 * Photograph-developed latents with and without identifying markings and scale.

Preservation of Fingerprint Evidence

 * The primary precaution in all cases is the prevention of adding fingerprints to evidence, or of destroying those already present.
 * Most fingerprints submitted will be on paper, glass, metal, or other smooth surfaced objects. When articles containing latents must be picked up, touch as little as possible, and then only in areas least likely to contain identifiable latents, such as rough surfaces.
 * While gloves or handkerchiefs may be used to pick up such exhibits, any unnecessary contact should be avoided. Although using a cloth to pick up exhibits prevents leaving additional prints on the articles, the cloth will frequently wipe off or smear any prints originally present, unless great care is taken.
 * Large articles containing latents such as glass, metal articles, and firearms should be placed on wood or heavy cardboard and fastened down with string to prevent shifting and contact with other objects in transit. Where such evidence is to be examined frequently, a pegboard should be obtained on which wooden pegs can be moved as desired to support exhibits and keep them from moving. Bottles and glasses may be placed vertically on a board and placed in the bottom of a box. The base of the bottle or glass can be surrounded with nails to hold it in place, and the top can be either inserted through a hole in a piece of cardboard or held in position with a wooden board nailed to the container's lid.
 * Papers and documents containing latent prints should be placed individually in a cellophane or manila envelope. Such a container can be sandwiched between two sheets of stiff cardboard, wrapped, and placed in a box for mailing.

=**Glass**= Windows are frequently broken in burglaries, headlights in hit-and-run cases, and bottles or other objects may break or leave fragments on personal belongings of suspects involved in various types of crimes.

**Recovery of Evidence Samples**

 * Shoes and clothing of suspects or other objects contaminated with glass should be wrapped in paper and submitted to the Laboratory for examination.
 * All glass found at hit-and-run scenes should be recovered. The search should not be limited to the point of impact, since headlight glass may be dropped off at some distance away as the car leaves the crime scene. Glass from different locations should be kept in different containers. All glass should be collected because more than one type may be present. In addition, if just a few representative samples are saved, individual pieces that could be physically matched with glass remaining in the headlight shell of the suspected vehicle may be overlooked.
 * Place small glass fragments in paper wrappers, then in coin envelopes, pill boxes, or film cans which can be marked and completely sealed.
 * Place large glass fragments in boxes. Separate individual pieces with cotton or tissue to prevent breakage and damaged edges during shipment. Seal and mark the box containing them.

Standards for Comparison

 * **Windows:** If the broken window is small, send the whole window or all glass remaining to the Laboratory. If the window is large, recover several samples from different areas of the window. If the evidence glass is large enough for physically matching the broken edges or comparing the fracture lines, hackle marks, surface abrasions or contamination, the whole broken window is necessary.
 * **Auto Glass - Auto Headlights:** All glass remaining in the shell should be recovered. If it is suspected that a new glass has been installed, this should be removed and a careful examination made for small chips remaining in the shell from the previous lens which is broken. In such cases, also submit the new lens to the Laboratory.
 * **Other Glass:** When bottles or other glass objects are broken, recover all remaining glass.

=Tool Marks=

Nature of Evidence
Tool marks are encountered most frequently in burglary cases but may also be found in other types of crimes. The evidence consists of striations or impressions left by tools on objects at the crime scene and various types of tools found in the possession of suspects. In other cases, it is possible by means of physical and other comparisons to prove that parts of tools left at crime scenes were broken from damaged tools found in the possession of suspects. In many cases, it is possible to identify the specific tool which made the questioned marks by means of a Laboratory comparison of tools and marked objects. In some instances, it is also possible to prove that marks of various types on tools were produced by objects which they contacted at crime scene.

Preservation and Packaging of Tools

 * All areas on recovered tools which contain transferred paint, building material, or other contamination should be wrapped in paper and packaged to prevent the prying blades or cutting edges .'rom contacting any other surface or object.

Make No Tests With Tools

 * Attempts should never be made to fit tools into questioned marks or to make test marks prior to Laboratory examination. If done, the questioned mark or tool may be altered and this may make any Laboratory examination valueless. In addition, traces of transferred paint or other stains on the tool may be lost or additional material may be transferred to the tool.

Preservation of Tool Marks

 * Whenever possible, submit the whole object containing tool marks to the Laboratory instead of just removing the area containing the mark. If this is not possible, carefully photograph and sketch the area containing the mark. Although this photograph will not be sufficient to allow the Laboratory to perform a toolmark comparison with the tool, it will assist the Laboratory to determine how the mark was made so that test marks can be-more easily made.
 * Casts of tool marks can be made by a person who has had considerable experience in this work. Poor casts are useless for comparison purposes and some marks will be damaged if improper methods are used.
 * Pack the object containing tool marks so that no alteration or damage will occur during shipment. Small objects should be wrapped with clean paper and placed in envelopes or boxes, while important areas on larger objects can be protected with paper. Whole, large objects can be packed in cartons or crates, if not delivered in person.