crime scene investigation

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recorded. A good technique to use indoors on hard floors is the oblique lighting technique (also known as side-lighting). ...... blood , urine and faeces , tumbler or other utensils used .... vogue for preliminary screening and collection physical ...
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FORENSIC SCIENCE

CRIME SCENE INVESTIGATION -RAN B. SINGH*

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HE investigation of crime is in fact a dynamic process of formulation and testing of hypotheses of crime. A hypothesis is formulated in the light of the scene of crime and the information obtained from the victim, suspects, eyewitnesses, and others present there before arrival of the Investigating Officer. The expertise and experience of the Investigating Officer also plays a very important role in formulating the hypothesis. The crime scene investigation yields physical clues of crime. The hypothesis is tested in the light of the new facts available from the investigation of the scene of crime. If the facts do not fit in the hypothesis, it is revised and tested again after scientific evaluation of the physical clues. Additional information, as and when available, necessitate the testing and revision, if needed, of the hypothesis of crime. This process continues till the crime is reconstructed and solved. A systematic and diligent investigation of the scene of crime is of paramount importance in testing and verifying the hypothesis of crime beyond reasonable doubts. The physical clues of crime provide answer to the who, what, when, where, why, and how questions of events and elucidate the circumstances of a crime. The objective of crime scene investigation is to help establish what happened and to identify the prepetrator. Crime scene investigation is a difficult and time-consuming job and there is no substitute for careful and. thoughtful approach . The crime scene investigation can be divided, broadly, into the following activities:• Protection of the scene of crime • Documentation of the crime scene conditions • Photography/sketching of the scene of crime • Search of the scene of crime for physical clues • Preservation, packaging and forwarding the physical clues.

PROTECTION OF THE SCENE OF CRIME The most important aspect of evidence collection and preservation is protecting the crime scene. This is to keep the pertinent evidence uncontaminated until it can be recorded and collected . The successful prosecution of a case can hinge on the state of the physical evidence at the time it is collected . The protection of the scene begins with the arrival of the first police officer at the scene. While approaching the scene of crime the Investigating Officer, should be alert for discarded evidences. The approach and escape routes should be examined carefully. He should take control of the crime scene and should determine the extent to which scene has thus far been protected . The information regarding any change/ disturbance should be obtained from persons, who have entered the scene before arrival of th e Investigating Officer, to know the original conditions. The crime scene and any other areas, which may yield valuable evidence, should be roped off to prevent any further disturbance o f the scene and contamination of potent i al phys ical clues . Unauthorized persons should not be allowed to enter the crime scene and a record should be kept of those who enter/leave the crime scene . DOCUMENTATION OF THE CRIME SCEN E CONDITIONS The purpose of the observation and documentation of crime scene conditions is to note the location of potential evidence and to mentally outline how the scene will be examined. The crime scene conditions should be carefully observed and transient details, such as lighting (on/off), newspaper. on the door/in-house, curtains (open/closed) , weather, temperature , movement of furniture , or oth er disturbances made in the life-saving efforts, conditions which would support or refute suicide/self-defence (gunshot residue , position of fi rearm in cases of shooting), etc. should be recorded. It is also important to be able to recognize what should be present at a

· Forensic Science Laboratory, U P , Mahanagar, Lucknow-226 006

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CBI Bulletin, August 2000

scene of crime but is not there, e.g. victim's purse, watch, ornaments, vehicle, etc. Similarly, the objects which appear to be out of place and might have been left by the perpetrator should be taken note of. If vehicles are involved in a crime, details of licence (identification) number, position of key, gear shift position, meter reading, steering position, amount of fuel in the tank, lights turned on or off, etc. should be recorded. A good technique to use indoors on hard floors is the oblique lighting technique (also known as side-lighting). A good flashlight with a strong concentrated beam is the only tool needed. The flashlight is held about one inch from the floor. The beam is then angled so that it just spreads over the floor surface and is almost parallel to the surface. The light is then moved back and forth . Any evidence, such as trace evidence and shoeprints, will show up dramatically. Under normal lighting conditions, this evidence may be barely visible or completely invisible. In addition to the floors, the ceiling should also be examined extensively . Th is may yield such valuable evidence as blood spatters and bullet holes. Writing, tape recording , and videotaping may be used for the documentation of crime scene conditions. If available, videotaping should be preferred for documenting a scene of crime. It can provide a better perspective on the crime scene layout. The comments on the crime scene conditions and other relevant information can also be recorded on the audio portion of the tape. The videotaping should begin with a general overview of the scene and surrounding area, and it should continue throughout the crime scene using wide angle, close-up, and even macro (extreme close-up) shots to demonstrate the layout of the evidence and its relevance to the crime scene. If videotaping in a residence, the camera can show how the pertinent rooms are laid out in relation to each other and how they can be accessed. This is sometimes lost in photographs and sketches. A keen observation and meticulous note would be beneficial at the time of the evaluation of the physical clues, and in reconstruction of the events of crime. The process of observing/documenting crime scene conditions should not degenerate into a sporadic and unorganized attempt to recover physical evidence. Under normal circumstances, evidence should not be collected in this process.

PHOTOGRAPHY/SKETCHING OF THE SCENE OF CRIME After the preliminary survey and observation of the crime scene has been conducted, it should be

recorded exhaustively by photography/sketcl1ing . It may be mentioned here that even if the videotaping of the scene of crime has been done, it is absolutely essential th at still photographs be taken . The photographs of many physical clues like fingerprints, footprints , blood spatters, bullet holes, etc. are essential for the examination and assessment of the importance of the clues. Before photographing, it should be carefully planned and all the photographic efforts should be recorded systemically. The overall, medium, and close-up views of the scene should be photographed successively. Suitable scale or other size determination devices should be used , whenever applicable. Areas adjacent to the crime scene, e.g . point of entry and exit, etc . should also be photographed. If feasible, efforts should also be made for aerial photography as well. The items, places, etc. fhat corroborate the statement of witness, victim and suspects should also be photographed . One should not hesitate to photograph even something, which has no apparent significance at that time, because it may prove to be important later. The photographs should be taken from eye level when feasible so that they exhibit the scene, as it would be observed by normal view. The physical clues should be photographed in place before its collection and packaging using size determination device, if necessary. The sketch/diagram of crime scene establishes distance size relationship between various objects in the scene and supplements photographs. A sketch is usually made of the scene as if one is looking straight down (overhead sketch) or straight ahead (elevation sketch) at a crime scene. Initially, a rough (not to scale) sketch is drawn at the scene of crime and distances/size of the objects are noted down. Two measurements takeh at right angles to each other or from two reference points will usually suffice in placing the objects where they belong in a sketch. Double measurements should be taken to make sure they are correct. This is especially true where calculations will be done later. The rough sketch is used as a model for finished sketch. The details of the case, e.g . FIR number, police station , location , time, compass orientation (direction), measurements, legends, name of the preparer, etc. should be recorded on the sketch. The sketching should, in general, progress in the following manner : layout of basic perimeter, setting of fixed objects like furniture etc., recording of the positions of evidences, record ing of appropriate measurements, recording of compass orientation, and writing of key/legends, etc. A final sketch can be made later using inks, paper, and ruler, or a computer. The original rough sketch should be retain ed and preserved in case it is needed at a later date. O nce the scene has been docum ented, it shou ld be

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air-dry, wrapped in paper and is put in paper bags. For sex offence cases, the victim should always be examined by a physician and the relevant evidences are collected by him. All the garments, such as undershorts, panties, or other exhibits are labelled, packaged and sealed separately. The fabrics with seminal stains should be handled as little as possible. Damp fabric should be allowed to dry completely before packaging. Plastic containers should not be used for packaging physiological fluid evidence. (ii) Hair An examination of human hair can occasionally reveal the possible race/sex of the individual from whom it came and the part of the body from which it is originated . Human hair can be compared to determine whether or not two samples could have had a common origin. The value of the laboratory examinations of such specimens will depend upon the amount of hair recovered and the characteristics found in the examinations. All the hair available at the scene of crime should be recovered . If possible, the fingers or tweezers should be used to pick up hair. The hair samples should be wrapped in paper and placed in small envelopes, which should then be folded and sealed in larger envelopes. The outer sealed envelope should be labelled. If hair is attached, such as in dry blood, or caught in metal or a crack of glass, attempt should not be made to remove; it should be left intact on the object. If the object is small, it is marked, wrapped, and sealed in an envelope. If the object is large, the a,rea containing the hair is wrapped with paper to prevent loss of hairs during transit. In rape cases, the victim's pubic region should be combed prior to collecting standards. Known hair samples from the victim, suspect, or any other possible sources should be obtained for comparison with unknown specimens. The recommended method for collecting head hairs is to start by having the person from whom they are being collected bend over a large sheet of clean paper, rubbing or massaging his hands through the hair so that loose hair will fall out on the paper. More should then be gathered by plucking them from representative areas all over the head . A total or 50-100 hairs is desired.The hair should not be cut. This same method may be used to collect hairs from other parts of the body. 30-60 pubic hairs are required . When the person is a suspect, hair should be gathered from all parts of the body even though there may only be an interest in hair from the head at that particular time.

(iii) Fibres and Threads 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, protruding nails, broken glass, or other locations. Examination of fibres can normally be conducted to determine the type or colour of fibre . Such examinations will sometimes indicate the type of garment or fabric from which they originated. Fibres and threads can also be compared with suspect's clothing to determine whether or not they could have come from his clothing. If threads or large fibres are found , they can often be picked up with the fingers and wrapped in paper and then kept in a small envelope, which can be sealed and marked. Loose fibres should never be placed directly into a mailing envelope since they can be lost from this type of envelope . If the fibres are short or few in number, and if it is possible to do so, the area contain ing the fibres or th e entire item containing the fibres should be wrapped in paper and the whole exhibit is sent to the laboratory. In sex offences, assaults, and some other cases, it may be possible to indicate or demonstrate contact between two individuals or between an individual and some other object, such as a car seat, by comparing fibres. Wh en fibres or threads are recovered, all clothing of persons from wh ich th ey might have originated should be sent to the laboratory f or comparison purposes. (iv) Glass

Windows are frequently broken in burglaries, headlights in hit-and-run cases, and bottles or other objects may break or leave fragm ents on personal belongings of suspects involved in v arious types of crimes. In case of burglari es, shoes and c loth ing of suspects or other objects contaminated with glass should be wrapped in paper and submitted to the laboratory for examination . Large glass fragments should be placed in boxes, separating indiv idual pieces with cotton or tissue paper to prevent breakage and damage during transit. The box is sealed and marked before forwarding to the laboratory. All glass found at hit-and-run scenes should be recovered. The search should not be limited to th e point of impact, since headlight glass may be dropped off at some distance away as the car leav es the crime scene. Glass from different locations should be kept

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in different containers. All glass should be collected because more than one type may be present. It would also be of help in physical matching of broken pieces. Small glass fragments should be wrapped in paper and then in small envelopes, pillboxes, or film cans that can be marked and sealed. Standards (known samples) are also collected and forwarded to the laboratory for comparison . If the broken window is small, the whole window is sent to the laboratory for comparative studies. If the window is large, several samples from different areas of the window are collected . 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. In case of auto headlights, all glass remaining in the lamp socket should be recovered for comparison. 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 socket from the previous lens which is broken. In such cases, the new lens is also submitted to the laboratory. When bottles or other glass objects are broken, all remaining glass should be recovered and forwarded to the laboratory for comparison with the evidence glass. As part of the investigation of vehicle accidents, it may be of importance to determine whether or not a headlight or tail light was illuminated at the time the light was broken. In such cases, recovery of the filaments is of primary importance. These are quite small and their location may require a careful search . If recovered, they should be wrapped in a paper or placed in a small pillbox, and sealed with tape. Whether or not the large filaments are located, all remaining parts of the lamp socket, glass envelope, or sealed beam headlight unit should be wrapped in paper and saved for laboratory study. (v) Paint Paint evidence is frequently encountered in hit-and-run, burglaries, art forgeries, and occasionally in other types of offences. In hit-and- run cases, paint may be transferred to clothing of victims. All the areas are examined , with particular attention being paid to areas showing pressure effects (glaze etc.), tears, or other contact. If paint is found on the garment, it should not be removed, the garment should be marked, carefully wrapped by rolling it in paper and sent it to the laboratory. Such paint will at least show the colour of relevant part of the responsible car. It must be

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modern cars have remembered , however, that manr t transfrerred only on the car more than one colour and the pain represents the colour of the pa~i~ular a~:~ely will an 'ndicat e the that made contact with the v1ct1ms.. examination of paint transfer on clothingd1 . ce only make and model of the vehicle involve ' sin II th portions of the top layer on e. ca;sa::;~e~! ~~e~ transferred. In addition, man~ vehicle be different using colours and types of paint th at may . d by the automobile manufacturer. f red from those specif 1e Sometimes whole chips of paint will be trans er to the clothi~g . If these flakes contain sever~I laye rs, and in particular if they come from a repainted car the~ such eviden'ce may have great val~e when the responsible vehicle is located. Chips 0 paint_may al~ be found on the ground near the point of impact in

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some cases. samples for comparison should be obtained from all areas showing fresh damage on suspected vehicles. This is very important since the paint may be different in type or composition in different areas, even if the colour is the same. If bending the metal slightly can flake off the paint, it should be removed in this manner. If not, the paint should be scraped or chipped off, using a clean knife blade. The blade should be wiped carefully, before collecting each sample . All layers down to the metal should be collected. Each sample should be placed in a separate container. Cross-transfers of paint commonly occur in hit-and-run cases of two or more vehicles. Loose paint chips should be removed and wrapped in paper. If, however, the transfers are smeared on the surfaces flake off chips or scrape paint from the vehicle ' including the transferred paint, as well as the top laye~ of paint originally on the car. All of these transfers recovered from different area.s should be kept in separate containers. The samples should not be placed directly into envelopes . In case of cross-transfers, uncontaminated samples should ~lways_ be collected from each vehicle from areas ~mmed1ate_ly adjacent to each transfer collected . This is of great importance, since such specimens e ·t th~ laboratory to distinguish between the tran:r rm~ paint and the paint originally present on the veh~~: . Tools used to gain entry into build" other places in burglary cases ofte mg , ~afes, or of paint, as well as other subst~nces ns~~~tam trac~s safe insulation , etc. Care must be k as P ast1c , traces are not lost. If such transfers ~a e~ that such the end of the tool containing th ~ e present , wrapped in clean paper and e matena_ l should be prevent loss. Attempts sho ldsealed with tape to u never be made to

CBI Bulletin, August 2000

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• I the paint sam es m se rate containers. Paint sa pies au ne er e e t directly in o en elopes unless large pieces are e d osed. ost en etopes a e unsealed era s 1 the comers and loss or contamina i can r. (vi) Fireanns/Bullets/Cartridge Cases

A loaded gun should never be submitted to the laboratory, unless it is delivered in person. Unfired cartridges may be left in the magazine of a weapon, provided the magazine is removed from the gun. A firearm with the cartridge in the chamber should never be sent by any method, even if the weapon is not cocked or on safey. The bore, chamber, or cylinder should never be cleaned before submitting a fireann. and no attempt should be made to fire the gun before it is examined in the laboratory. A weapon should never be picked up by placing a pencil or other object in the end of the barrel. Serial number. make, model, and calibre of the weapon shou ld be recorded immediately after its recovery, and it should also ~e marked for identification. Weapons are placed in strong cardboard or wooden boxes, well packed, to prevent shifting of guns in transit. Rifles or shotguns should not be taken apart. If blood or any other material, which may pertain to an investigation, is present on the gun, a clean paper should be placed around the gun and sealed with tape to prevent movement of the gun and loss of the sample during transit. Recovered bullets should be wrapped in paper and sealed in separate labelled pillboxes or envelopes . No attempt should be made to clean recovered bullets before sending them to the laboratory. Bullets recovered from a _body should be air-dried and wrapped in paper. Washing may destroy trace evidence. All evidence bullets recovered should be sent to the laboratory. A conclusive identification may be possible on only one of several bullets

Gunshot residue is e ctrem ly f1 gil vid n should be collected as soon as possibl (pref within three hours of the discharg of fir am1) . In th case of live subjects, if more than si hmu hav passed or if the subject has wash d his h nd , it is unlikely that meaningful r suits will b obt in d. If a body is to be sampled, wh nev r pos ibl . gunsl, t residue collection should b p rfonn d prior to moving the body. If this is not possibl . th hands h uld b protected with paper bags. (vii) Serial Number Restoration

In many cases, oblit rat d s ri I numb I an be restored . If the restoration of ms did ntifi nllon

CBI Bulletin, August 2000

number/marks is desired, the portion containing th e obliterated number/mark should be well protected before sending to the laboratory to avoid scratches and further damage to the relevant area . (viii) Too/ Marks

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 of tools were produced by objects that they contacted during commission of the crime. 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. Whenever possible, the whole object containing tool marks should be submitted to the laboratory instead of just removing the area containing the mark. If it is not possible to send the whole object, only the area containing the mark should be sent, and photograph of the mark showing the area in the whole object should be taken and sketch should also be made. It will assist the laboratory to determine how the mark was made and the exemplar/test marks can be more easily made. A person who has had considerable experience in this work can make casts of tool marks. Poor casts are useless for comparison purposes and some marks will be damaged if improper methods are used. The object containing tool marks should be packed in such a way that no alteration or damage will occur during transit. 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. Large objects can be packed in cartons or crates, if not delivered in person . (ix) Questioned Documents

All questioned documents involved in a particular investigation should be submitted to the laboratory

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. . . rt t ·nee questioned for examination This is impo an s1 . . on of docume nt s are id en tified by a comparis or similarities , plus an absence of_?iv~rgetu~;~lent dissimilarities. In order to make ident1f1~at10~, must be handwriting, typewriting, or ot her e~1de~c~aterial in available. This means that all quest,one needed.

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It is very important to have su fficient ha~dwriti~~

exemplars or known specimen for com_p anson the questioned document. One or two s1gnat_ure a suspect's driver's licence or an identity ca_rd , ,_n ~an~ cases , does not contain suffi cie ~t ind,vi~~ae cha racteristics to draw a co nc lus ion . In ~ instances such an examination may substanti ate a suspicion' and this should be conside red as an investigational lead. To support th is, it is necessary to obtain and examine additional standards. K~own specimens that were made in business tran:act!ons, such as receipts, promissory notes, appl1cat1ons, letters filled-in forms , etc. represent, in most cases, the ind\vidual's most normal writing . It is significant in many cases that these writings are of the same date (period) as the questioned document. It is important to obtain request specimens from a suspect at the earliest ; the suspect may be uncooperative at a later date. The conditions surrounding the preparation of the questioned document should be duplicated as nearly as possible when the request exemplars are obtained. The same or similar colour and type of paper and ink, and instrument should be used for the request writing , as that used to produce the questioned document. If the suspect document is, for example , a threatening letter and the note is either handwritten (cursive) or block lettered, the same style should be requested from the writer. Persons should be asked to write their names and addresses several times with brief personal histories. This should be removed and another sheet of paper furnished. The exact words and numbers that appear on the questioned document should be dictated. This should be done five/six times on separate sheets, removing the specimens from the writer's view as they are produced . If it is a case involving cheque, the specimens should be taken on blank cheques or slips of paper of the same/ appropriate size . The number of specimens necessary for identification in any specific case cannot be d_etermined, therefore, repeatedly written spec1~ens as above must be obtained for eac h questioned document. _When securing typewritten exemplars, several copies of the questioned documents should be made on the suspected machine using light, medium and

CBI Bulletin, August 2000

heavy touches. At least one copy should be made with the ribbon removed from th e machine or the ribbons set on stencil, and the keys allowed to strike dlr~ctly on a sheet of new carbon paper, which should be inserte9 on top of the paper used for the specimen. This provides clear-cut exemplars of any machine's typeface, showing disfigurations in type characters. The exemplars should always be typed on the same type and colour of paper as that used for th e questioned document. Und er no circumstances should either th e question ed document or the exemplars be marked, defaced or altered. No new folds should be made, nor should marks or notes be placed on such material. Personal marks for identification purposes should be made as small as possible on the back or other area of the document where no handwriting or typewriting is present. Whenever possible, all documents should be protected by placing them in cellophane or plastic envelopes. Que stion ed documents may be submitted personally. If such evidence is sent to the laboratory by post, it must be sent by certified or registered mail. If there is a massive amount of material, it may be sent some other way, but the package must always be sealed.

If the examination and decipherment of charred paper is required, great care must be taken to prevent any additional crumbling or breaking apart of the burned material. Normally, it should be placed on top of loose cotton in a box and delivered in person to the laboratory. No smatter how it is packaged , such material will be damaged if attempts are made to send it by post. In addition to handwriting and typewriting comparisons and the decipherment of charred documents, the laboratory can conduct many other related examinations. These include, but are not limited to : restoration or decipherment of altered, obliterated, or erased writing, comparison of cheque protectors and rubber stamps with questioned printing, identification of embossed or indented writing or typing, comparison of paper and commercial!Y printed material, such as checks, coupons, receipts, and others, physical matching of cut or torn paper of various types, problems relating to inks. (x) Fingerprints

There are three kinds of crime scene fingerprints : visible prints (impressions left on surfaces after touching coloured materia_ls), plastic pri_n ts (impressions left on soft material), and latent prints

(Impressions caused by transfer of body perspiration). Visible or plastic prints can be located at the scene of crime without much difficulty . The techniques of developing (visualizing) latent prints would depend on the type of surfaces bearing the print. Latent prints on hard and non-absorbent surfaces like glass, tiles, pol ished wood , etc. can be d ev eloped by th e application of fingerprint powders, while those on soft and porous surfaces like paper, cardboard , etc. require treatment with chemicals. The gray and black powders are adequate for developing most latent prints. Th e magnetic-sensitive powder (u sed for Magna Brush), and fluorescent powders are also used to develop latent fingerprints. Iodine, ninhydrin, and silver nitrate are generally used to develop most of the latent prints on soft and porous surfaces. Recently, a chemical technique known as Super Glue fum ing has gained wide acceptance for developing latent prints on non-porous surface. The use of lasers and other commercially available high intensity alternate light sources for developing latent prints are also in vogue today. The alternate light source system gives more flexibility in selecting suitable radiation for exposing the suspected areas to search latent prints. The fingerprints , visible, plastic, and developed latents, must be photographed with close-up lens or fingerprint camera. The prints developed with powders can be lifted with a broad adhesive tape and preserved by placing the tape on a previously labelled card. All the articles having latent fingerprints should be marked in some distinctive manner, such as is th e case with any other type of physical evidence. Precautions should be taken, when marking evidence, not to damage or destroy potential latent fingerprints. Lifted and developed latent fingerprints should also b~ marked or sealed in marked envelopes. The primary precaution in all cases is the prevention of adding fingerprints to evidence, or of destroying those already present. Most fingerprints would be on paper, glass, metal, or other smooth surfaced objects. When articles containing latents must be picked up, it should be touche_d as little as possible and then also only in areas least likely to contain identifiable latents, such as rough surfac~s. While gloves or handkerchiefs may be used to pick up such exhibits, any unnecessary c?ntact sho_ul? be avoided . Although using a cloth to pick u~ exh1b1ts prevents leaving additional prints on the articles, the cloth will frequently wipe off or smear ~ny prints originally present , unless great ca re 1s taken . Larg~ articles containing latents, such as glass, metal articles, and firearms should be placed on wood

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or heavy card broad and fastened down with string to prevent shifting and contact with other objects In transit. Where such evid ence is to be handled 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 . Th e 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 cellophane . Such a container can be placed between two sheets of stiff cardboard, wrapped and sealed.

(xi) Footprints The impressions/prints made by bare foot or footwear is, in general, termed as footprints. The value of footprint evidence is subject to th e individual features and ridge characteristics (for bare foot) ; flaws, irregularities , worn-out design on the sole, nails, patchwork, worn out heel, etc. (for footwear), which provide points of comparison for positive identification. On the other hand, footprints, shoe prints, wh ich show only dimensions and pattern or general shape, can be used only to eliminate a suspect or corroborate some other evidence. '

Depending upon the surface on which the prints are made, footprints may be classified as surface footprints or sunken footprints . The methods . commonly used for recording/lifting footprint~ are photography, tracing , lifting and casting . While photographing the footprint one should ensure that the lens of the camera is parallel to the footprint and the aperture is small (for better depth of field) . An identification card and scale should be placed by the side of the footprint. For tracing the surface footprint, a glass (or a celluloid sheet) is held as close to the print as possible. The contour is drawn by sketch pen and the details of crease, etc. are carefully traced. Surface prints (made of dust, etc.) may be lifted on photo bromide paper. The fixed bromide paper is moistened by soaking it in water for a few minutes and is kept with emulsion side down on the print. Uniform pressure is applied on the bromide paper so that the dust particles get attached to gelatin surface. Electrostatic technique is another useful method to lift dusty prints. A black vinyl sheet is placed on the area having the footprint. The vinyl sheet is covered with aluminium foil through which a high voltage is passed. The dust particles of the print get attached to the vinyl sheet.

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unken footprlnt'i f:lr llftm1 blf rflfJ~lny ttirm ::1••1 n10 ca t i•, gr_m ornlfy rno