PERSONAL-IDENTIFICATION.CHAPTER-7.pptx..

educational purposes

1. Value of fingerprint as Evidence Fingerprint evidence plays a vital role in criminal investigations because person’s fingerprints are unique and do not change during the course of their life. Fingerprints can be used to quickly and efficiently confirm or disprove a person’s identity like in checking a suspect at a border crossing. Latent prints collected at a crime scene have the potential to link a series of crimes together, or to place a suspect at the scene. it is also important role in identifying victims following a disaster such as a cyclone, earthquake, bombing or other attack.

2. LATENT PRINTS Has been defined as the markings of oily matter or perspiration from the skin glands left upon surface which the hands and fingers may have touched. it is best described as a combination of chemicals which is exuded by the pores on the surface of the skin.

3. How latent prints are produced? The skin over most of the body is relatively smooth. Skin consist of tiny raised lines or “friction ridges” however, are found on the digits, palms and soles. They are called ‘ friction ridge’ because of their biological function to assist in our ability to grasp and hold onto objects. Present on the tops of the friction ridges are very minute sweat pores that are constantly exuding perspiration. This perspiration adheres to the surface of the ridges. When the friction ridges come into contact with a suitable surface, this perspiration is transferred to that surface, leaving a recording, or print of the friction ridge. This impression of friction ridge skin is comprised mostly of sweat but may also contain a variety of contaminates such as oil and dirt.

4. Chance Impressions These are impressions left by chance at the crime scene

5. Types of Evidentiary Fingerprints 1. VISIBLE PRINTS - Often impress on dust, blood oil or grease. MOLDED PRINTS - Those marks on the surface whenever fingers touch soft objects. 2. INVISIBLE PRINTS - Those prints that are made due to the sweat present in the fingers and thumb of a person that is transferred to any object that he holds.

6. Types of Evidentiary Fingerprints SMUDGE PRINTS - Those prints that are indistinct due to sliding motion of fingers at the time they are impressed. FRAGMENTARY PRINTS - Those prints that show only a portion of the pattern or of the friction skin.

7. Types of Evidentiary Fingerprints PLASTIC PRINTS (Plastic Impression) . Prints formed on plastic material, such as melted paraffin from a pitch, paste on envelope and stamps. This type of friction ridge impression is molded into the surface of material such as putty or modeling clay forming a three dimensional impression. Latent impression - This type of friction ridge impression is not readily visible. The term ‘latent’ is commonly applied to all chance or unintentional impressions that are of evidentiary value. Patent Impression - This type of friction ridge impression is visible e.g. an impression found in blood. Plastic Impression - This type of friction ridge impression is molded into the surface of material such as putty or modelling clay forming a three dimesional impression.

8. Factors affecting Latent Fingerprints 1. CLIMATIC CONDITION Too much exposure to the elements would reduce the chance of their being recovered due to the following: A. Heavy condensed moisture as rain, snow or dew will immediately erase fingerpritns . B. Excessively high temperature caused by direct rays of the sun during summer months can destroy them in a matter of few minutes C. Winds due to warm temperature will cause the disappearance of fingerprint evidence because of the increased evaporation of watery substance. D. Dust accumulated on finger impressions obliterates the identification of ridge characteristics.

9. Factors affecting Latent Fingerprints 2. SUBJECT FACTOR - This refers to the physical characteristics of the individual. The distinction is deciphering finger marks left by a male or female human being. The friction ridges or prints belonging to young female adults are found to be finner than those of men. 3. Nature of the Surface - Latent fingerprints left on a smooth non-porous surface will formally retain their usefulness longer than those impressed on a porous surface. These very rough surfaces may retain the deposits of latent print residue, but it is impossible to decipher the ridge characteristics left behind due to the nature of the recieving surface.

10. SWEAT CONTENTS 1. Amino Acid 2. Water 3. Salt 4. Oil Purposes of Sweat 1. Regulate temperature of the Body 2. Moisten the skin 3. To remove waste and other toxic materials 4. Means of identification

11. Latent Print Development Latent print development requires knowledge and skills to ensure before a friction ridge identification specialist can enhance a print, he/she must first find it. In most cases this is easier said than done. Recognition of the areas where one is most likely to find latent prints is an extremely important step in the examination of latent print evidence. Once the potential area which is most likely to yield fingerprint evidence is selected, a variety of techniques such as physical and chemical methods can be used to process the surface and to develop friction ridge impressions.

12. Three important factors in the selection of methods in the development of latent prints Nature of the surface example: porous or non-porous, wet, dirty etc. The apparent composition of the fingerprint residue or matrix (e.g. moisture contaminated with oil and dirt and; Condition of the friction ridge impression. Steps in the examination of any potential latent print Visual Examination Fluorescene examination Selection and application of an appropriate enhancement method (s) – physical and/or chemical and or digital enhancement followed by photography after each process.

13. Materials For Collection of Latent Fingerprint Fingerprint powders – refers to the powder use in developing latent prints found at the scene of the crime. They are normally found in two; the black and white or gray, which is applied depending upon the contrasting background. 2. Fingerprint brushes – used for developing latent prints using non-magnetic powder. There are three variations of brushes used: the fiber glass, magnetic and feather type. 3. Magnetic Wand – use in powdering latent prints using magnetic powder.

14. 4. Fingerprint Lifting tape – refers to a type used for lifting developed latent prints which is quite harder than an ordinary tapes. 5. Latent Print Transfer Card – refers to a card used in preserving lifted latent prints which is either white or black in background. 6. Fingerprint cameras – use in photographing the developed latent prints

15. Basis of Selecting the Powder COLOR – for proper or appropriate contrast ADHERENCE – avoid of slip and stick One of the oldest, most common and most readily available methods for the development of latent fingerprints is that of dusting a surface with a fine powder of contrasting color. The use of powders depends on the object upon which the search is being conducted. A wide range of powders is commercially available and their formulation differs with each manufacture

16. Latent Fingerprint Techniques PHYSICAL DEVELOPMENT When we touch something we leave behind some of our sweat and this in turn can leave behind an impression of the ridge detail on your fingerprint, thus leaving a fingerprint impression. A fingerprint can be left on may types of surfaces. It can be made visible by brushing it with a powder or treating it with chemicals in a laboratory. Similarly, if the fingers are coated with ink or another substance such as paint, oil or blood, then a permanent impression may be left on a particular item.

17. 2. CHEMICAL DEVELOPMENT – A ninhydrin solution of approximately 0.5% weight per volume in concentration is required to develop fingerprints on paper. To obtain the best contrast, ninhydrin developed prints should be photographed under white light with a green-yellow filter (560-580nm) fitted to the camera. Apply the solution on the paper by dipping, brushing or spraying and heat must be applied. The chemical react to amino acid present in the latent fingerprint which will be stained with a purple color.

18. Locate latent fingerprints Locating a latent fingerprint often requires vigilance. Latent fingerprints are suspected to be present on the point of entry, objects attacked and point of exit. The type of fingerprint left behind usually determines the amount of time and effort investigators must put into locating the print. The type of surface where the latent fingerprints are located serve as a basis in determining what appropriate development method is applied.

19. Nonporous Surfaces A powder technique is usually used to identify latent prints on nonporous surfaces such as glass, marble, metal, plastic, and finished wood. When powder is distributed on the surface, it adheres to the residue deposited from the finger’s touch, allowing investigation to find the print. Superglue fuming is a chemical process that exposes and fixes fingerprints on a nonporous surface. The process works by using an airtight tank, known as a fuming chamber, to heat up superglue (liquid cyanoacrylate) which releases gases that adhere to the oily residue of print, thereby creating an image of the fingerprint. This can be performed at the crime scene by using a handheld wand that heats up superglue and a florescent dye.

20. POROUS SURFACE The development of latent fingerprints using the powder method is not as effective on porous surface such as fabric, unfinished wood, and paper. The use of chemical methods to locate the print such as iodine fuming, silver nitrate, or ninhydrin is preferred. When the chemicals comes into contact with the chemicals present in the fingerprint residue (natural oils, fats), the print become visible.

21. Methods of Developing Prints: Dusting Method - considered as the simplest and traditional methods used in developing prints at the scene of the crime. (Use of Powder and Brush) Rolling Method - basically used in developing prints in paper done by simply rolling the paper with powder spreading in its surface. Fuming Methods - done by using chemical fumes such as Iodine and Ammonium Fumes. Silver Nitrate method – done by spraying a 5 percent solution of silver nitrate to the surface of the paper. Ninhydrin Method - is considered as one of the best method used in developing prints in paper. Laser Method - is a modern method of tracing and developing prints. Post Mortem Fingerprints - are prints taken from a diseased person.

22. Human Skin Latent fingerprints are also found and developed on human skin that gives difficulty to any technician. The problem encountered is finding the print since the oily residue left by fingers that creates the fingerprint itself is often present on human skin, making it difficult to create a contrast between the surface (skin) and the print. After a print is left on human skin, the oily residue often disperses and is absorbed into the skin, blurring the print. Two hours is the maximum amount of time that a print on skin may viable.

23. Methods of Fingerprinting a Living Person The skin is known as the largest organ and the first line of protection in the human body. It covers the body from head to toe and is referred to as friction ridge skin. Obtaining legible recordings of these areas of skin is vital for subsequent comparisons to latent impressions recovered from crime scenes, for comparison against previous records, or for input automated fingerprint identification systems (AFIS). Inked prints, record prints, standards, and exemplars are all terms that are used to describe the recording of these unique details. In taking the inked fingerprints of a living person, it considers the recording of the rolled impressions and plain impression.

24. ROLLED IMPRESSION - is an impression made or place in the fingerprint card which is taken individually by rolling the ten fingers of the subject 180 degrees from tip to the Second Joints PLAIN IMPRESSION - is an impression made simultaneously that serves as a reference impression PURPOSES OF THE PLAIN IMPRESSION : To serve as a guide in checking the rolled impression whether or not the rolled impression were properly place on their respective boxes. To check on the ridge characteristics of the plain impression, if the rolled impression is somewhat faint, or indistinct due to bad condition of the friction skin either temporary or permanently deteriorated or in case of a doubtful or questionable prints. To check the minute details of the ridge characteristics for purposes of classification and identification.

25. SCIENTIFIC WAY OF TAKING FINGERPRINTS Prepare the set – up for printing. Clean the inking plate/slab thoroughly before spreading the ink. Place a small amount of fingerprint ink on each side of the slab and in the center, then start spreading the ink using the roller back and forth until the ink is evenly distributed. To check whether or not the ink was spread properly or whether it is enough or not, try to print one of your finger or put the slab near the light and if brownish reflection is observe it means you have a good ink for used. Place the fingerprint card on the card holder properly to ensure that proper entry will be easy Check the hands of the subject. Make sure that it is clean and dry. If it is perspiring freely, wipe them off with a soft, clean cloth dampened with alcohol. The technician should stand at the left of the subject in taking right hand impression and take the right side in taking the left hand impression of the subject.

26. SCIENTIFIC WAY OF TAKING FINGERPRINTS 8. Subject should be instructed to stand straight but relax and not to assist the technician in rolling his finger. 9. In taking the rolled impression, technician should place first the right thumb to be rolled towards the body of the subject while the other fingers not in use is either folded or closed. Then inked the remaining fingers and rolled it away from the body of the subject. Make sure to roll the finger from the tip down to the beginning of the next joint, and from one side of the nail to the other (180 degrees). 10. Same should be done in the left hand only that the technician will turn to the right of the subject. 11. Apply only moderate amount of pressure in printing subject’s fingers to avoid blurred prints but hold the subjects hand firmly so as to prevent pulling that may cause smeared impression. 12. To obtain the plain impression, all the fingers of the right hand should be pressed lightly upon the inking plate, then press simultaneously upon the lower right hand of the card and do the same to the left hand