Collection & Storage of Biological Evidence Biological Evidence: Biological evidences are as follows1. Blood 2. Semen 3. Saliva 4. Vomit 5. Sweat 6. Hair 7. Fiber 8. Urine 9. Fecal matter Biological samples play an important role in analysis of crime. Biological samples establish relation with the victim or accused during committing crime. 1. Blood: Blood spot can be found red in colour. On Movable surface: Like Weapon, Glass, Paper, Cloth, Soil, Vehicle, Wood etc. On immovable Surface: Dead Body, Wall, Earth Surface, Windows, etc. Any articles like water tab , hanky , towel , bed sheet , pillow , blanket , certain ,mat also examined at the time of collection at crime scene, because criminal may come in contact with this article during committing crime. 2. SEMENIt is white or yellowish starchy fluid of the body. Semen is mainly found in the case of Sex assault, Rape etc on Inner garments or clothes of victim as well as accused, Bed sheet, Blankets, etc semen is also considered as an evidence and check all suspected place on cloth. 3. SALIVAWhite, Frothy and concentrated fluid and containing a mixture of Antigen and enzymes. Saliva is found on cloths, cigarette butt, bottles, cup, Hanky and also in the case of biting during assault. Hanging cases. Tobacco spitting and some time saliva is secreted continuously from mouth due to disease. 4. VOMITNature- It is Yellow, Green, Black Colour liquid containing undigested or partially digested food matter. It is found on Earth or cloths in the case of poisoning and in some critical diseases etc. 5. HAIRNature- It is a thin and dark black in Colour seems like thread. Hair is also considered as evidence in case of assault and also transferred by the means of contact. 6. FIBERNature- it is present in different Colour and structure. It is Soft delicate by nature. Many types are fiber is found at the crime scene like Animal fiber, Wood fiber, Vegetable fiber etc. and it is transfer by contact. Identifying biological evidence: Securing & Collecting Evidence 1. Evidence can be massive to microscopic 2. may only be detected in a crime lab ex. traces of blood on clothing, hair and fibers from vacuum sweeps 3. it is sometimes necessary to confiscate clothing from victim and perp 4. Critical areas should be vacuumed; sweepings from different areas must be kept separate 5. finger nail scrapings must also be taken from suspects and victims Securing & Collecting Evidence All evidence needs to be properly packaged, sealed and labeled. The evidence log should contain all pertinent information including: •Case # •Item inventory # •Description of the evidence •Name of suspect •Name of victim •Date & time of recovery •Signature of person recovering the evidence •Signature of any witnesses present Obtaining Standard/Reference Samples 1.Collect evidence from suspects and victims that are similar to the P.E. collected @ the scene paint from vehicles hair or blood 2. buccal swab 3. substrate control Reference Samples control samplemust be obtained from victim for purposes of exclusion *standard/reference samplephysical evidence whose origin is known, that can be compared to crime scene evidence. The presence of reference samples greatly facilitates the work of the forensic scientist. Ex: blood or hair from possible suspects to be compared to crime scene evidence. * Buccal swabswab of inner portion of cheek, performed to collect cells for use in determining DNA profiles * Substrate controluncontaminated surface material close to an area where phys evidence has been deposited; used to ensure that the surface on which a sample has been deposited does not interfere w/ lab tests Packaging the Evidence • Evidence is placed in a paper bindle. The size of the bindle depend depends on the size of the evidence. •Entire object should be sent to the lab. • Each different item must be placed in separate containers. Packaging evidence separately prevents cross contamination. •Unbreakable plastic pill bottles excellent containers for hair, fiber, • glass evidence • small amts of trace evidence can be conveniently packaged in a carefully folded paperdruggist fold: folding one end of the pape over 1/3, then folding the other end (1/3) over that, & the repeati Packaging Evidence Manila envelopes or sealable plastic bags can be used for some evidence. • •Wet evidence should NEVER be packaged in plastic containers while wet. •Bloodstained materials should NOT be stored in airtight containers b/c accumulation of moisture may encourage the growth of mold; in these instances wrapping paper, manila envelopes or brown paper bags are used. •All items of clothing must be air dried & place in individual separate bags. •Charred debris recovered from a fire must be sealed in airtight containers to prevent evaporation of volatile petroleum residue. (new paint cans or tightly sealed jars) Chain of Custody An evidence log and a chain of custody document must be attached to every evidence container. *Chain of Custodythe documented and unbroken transfer of evidence; list of all people who came into possession of an item of evidence (continuity of possession) Maintaining chain of custody is essential. Chain of Custody every person who handles the evidence must be accouted for · ·all items must be carefully packaged & marked upon their retrieval at the scene. ·Record to show collector’s initials, location of evidence, & date of collection. •Seal the evidence & the collector’s signature is written across the sealed edge. •When the package is reopened at the lab it is opened at a location other than the sealed edge. Every time opened: new seal, new signature, place in new evidence bag. ⚫ Aim :Sample is collected to conduct the forensic examination in order to prove or disprove whether there is a link between individual(s) & the objects and the place of evidence . ⚫ Forensic specimen collection techniques : ⚫ When collecting specimens for forensic analysis, the following principles should be strictly adhered to: ⚫ Avoid ⚫ contamination: Ensure that specimens are not contaminated by other materials. Wear gloves at all times. Modern DNA assay systems are very sensitive and may detect small amounts of extraneous material. Collect early: Try to collect forensic specimens as soon as possible.The likelihood of collecting evidentiary material decreases with the passing of time. Ideally, specimens should be collected within 24 hours of the assault; after 72 hours, yields are reduced considerably Handle appropriately: Ensure that specimens are packed, stored and transported correctly. ⚫ As a general rule, fluids should be refrigerated; anything else should be kept dry. ⚫ ⚫ ⚫ Label accurately: All specimens must be clearly labeled with the patient’s name and date of birth, the type of specimen, and the date and time of collection. Ensure security: Specimens should be packed to ensure that they are secure and tamper proof. Only authorized people should be entrusted with specimens. Maintain continuity: Once a specimen has been collected, its subsequent handling should be recorded. ⚫ Details of the transfer of the specimen between individuals should also be recorded. ⚫ It is advisable to check with local authorities regarding the protocols for the recording of such information. ⚫ ⚫ Document collection: It is good practice to compile an itemized list in the patient’s medical notes or reports of all specimens collected and details of when, and to whom, they were transferred. ⚫ Requirements : Common requirements are: handglooves,sterile swabs,sterilewater, syringes,scalpel or blade ,foreceps ,plastic wares,brownpaper, EDTA tubes,zip lock polyboxes,glass slides,preservates,tubes, lifting tape, clipper Pen/board marker cotton guage etc. Common biological samples encountered: ⚫ Whole fresh blood. ⚫ Blood stain( dry). ⚫ Seminal stain. ⚫ Hard tissue(bones). ⚫ Soft tissue (body organs). ⚫ Hair. ⚫ Buccal sample ⚫ Skin. ⚫ Finger nails. Methods of collection: ⚫ Whole blood sample: sterile needle should be used while collecting blood and put in EDTA vial.if blood is pooling then collect on sterile cotton or gauze pad. ⚫ Blood stain: should be picked up on sterile cotton guage using sterile foreceps and blade. If blood stain is, ⚫ On clothing,if possible,wrap the item in clean paper,place the article in a brown paper bag or box and seal & label container. ⚫ On small solid objects,send the whole stained object to the lab,after labelling and packaging. ⚫ On large solid objects:It is usually impractical to deliver the whole object to the Laboratory, scrape the stain onto a clean piece of paper, which can be folded and placed in an envelope. Seal and mark the envelope. . Do not mix dried stains. Place each stain in a separate envelope. . Never attempt to wipe dried stains from an object using a moistened cloth or paper. . Dried blood stain can also be collected by using lifting tape : For dried blood stains on a nonabsorbent surface, fingerprint lifting tape may be placed over the stain and lifted off. The stain is transferred to the adhesive side of the tape, which may then be secured on a clear piece of acetate for submission to the laboratory. ⚫ Seminal stain: Should not be touched by hand especially the stain portion. Should be picked up with sterile forceps. ⚫ Hard Tissues( Bones): Bones should be picked up using gloves, Kept at a place where there are no chances of environmental contamination. It should be allowed to dry completely. ⚫ Soft Tissues: Body organs should be collected using forces and wearing gloves. these should be kept in a sterile container. ⚫ Hair: Hair roots are preferred for the analysis. Hair roots should be picked up using sterile forceps. ⚫ Buccul sample: should be collected by using dry sterile swab in whole mouth between cheeks and gums,on and under tongue, in dentile fissures. ⚫ Skin: drip 3-4 drops of sterile water on swab & roll it on body with moderate pressure and immediately roll another dry swab on same area. ⚫ Fingernails: analysis for recovery of body fluids/DNA/other materials or comparison with broken fingernails at the scene. ⚫ Clip the fingernail of one hand at the time, over paper or drape & pack separately in addition to this swab under nails ,on surface of nail and around cuticle. Table :DNA content of biological samples TYPE OF SAMPLE liquid blood bloodstain liquid semen hair with root AMOUNT OF DNA 20000-40000 ng/ml 250-500 ng/cm2 150000-300000 ng/ml 1-10 ng/root liquid saliva 1000-10000 ng/ml oral swab 100-1500 ng/swab bone 3-10 ng/mg tissue 50-500 ng/mg Precautions for sample collection: ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ Wear gloves. Change them often. Use disposable instruments or clean them thoroughly before and after handling each sample. Avoid touching the area where you believe DNA may exist. Avoid talking, sneezing, and coughing over evidence. Avoid touching your face, nose, and mouth when collecting and packaging evidence. Air-dry evidence thoroughly before packaging. Put evidence into new paper bags or envelopes, not into plastic bags. Do not use staples. ⚫ Package all biological evidence in paper bags or envelopes (do not use plastic). ⚫ The packaging of biological evidence in plastic or airtight containers must always be avoided, because the accumulation of residual moisture could contribute to the growth of DNAdestroying bacteria and fungi. Preservation ⚫ Whole Blood: Blood should be collected in sterile container containing an anticoagulant. The mostly preferred is EDTA. ⚫ It should be mixed properly but gently for some time. The container should be covered with parafilm to avoid slippage. ⚫ Should be kept it at 40C or using ice during transportation till it reaches laboratory for analysis Blood stain: Blood stain should be dried properly. In semi dry stain there, is a possibility of bacterial growth thus chances of having contamination. ⚫ After complete drying it should be wrapped in a fresh blotting paper and packed in a Zip lock poly bag. ⚫ No preservative is required. It can be transported at environmental temperature. ⚫ ⚫ Seminal stain: Likewise seminal stain should also be dried properly. In semi dry stain there, is a possibility of bacterial growth thus chances of having contamination. ⚫ After drying it should be wrapped in a fresh blotting paper and packed in a Zip lock poly bag. ⚫ No preservative is required. It can be transported at environmental temperature. ⚫ Hard Tissue: No preservative is required. The hard tissues should be wrapped in the blotting paper and placed in a zip lock poly bag. ⚫ Soft tissue: It should be placed at 40C or in Ice till it reaches laboratory for analysis. ⚫ Hair: Hair roots should be placed in a blotting paper and then packed in a zip lock poly bag. It requires no preservative and can be transported at environmental temperature. ⚫ Buccul sample: should be collected on sterile swab and swab should be placed in tube. storage can be done by freezing. ⚫ Skin: sample collected by swab should be placed in tube and then in tamperevident bag. Storage by freezing. ⚫ Fingernails:collected by clipping on paper should be packed in zip lock poly bag/tamper evident bag along with clipper , swabs used should be placed in tube and store by freezing. Goals of Evidence Packaging Protects evidence against: •Loss •Contamination •Cross-transfer A-Suspect to victim B-Victim to suspect C-Scene to scene D-Item to item •Deterioration When Biological Evidence is Packaged Wet condition Evidence “leaks” through to the exterior of the container Resulting in Sample deterioration Sample loss Contamination issues A- Plastic Envelope Bag B-Paper Envelopes Bag Boxes This envelope is too sma for the evidence it is holding Small glass fragments can be lost from poorly sealed envelopes Ideally, these fragments would be packaged into a bindle first Sealing of Evidence • Sealing of evidence properly is a requirement of most • crime labs issues: Type of seal Need for identifying mark Where seal(s) is to be placed • Ways evidence can be sealed Heat seal Tape seal seal be initialed to document the person All Lock seals must sealing the evidence and dated to indicate when the evidence was sealed Seal should completely seal envelope flap Continue…. Seal should completely seal bag flap Example of Improper Sealing Staples are not an appropriate evidence “seal” Correctly Way of Sealing Evidence Tape seal across entire Flap of envelope Seal is initialed and dated Correctly Way of Sealing Evidence Tape seal across entire “flap” of bag Seal is initialed and dated Biological Evidence Packaging of Biological Evidence Insure the sample/Exibits is dry Do not dry in a heated air stream Use paper containers Immobilize evidence when necessary “sharps”: knifes, broken glass when stain could be dislodged Recommendations for Collection and Packing of Biological Evidence Collect and package stains separately--do not allow separate stains to come into contact with one another Sheets of paper can be used to minimize contact of stains on a bloodstained garment Consider packaging all biological samples separately A bloodstain swab and its control can be separately packed into two coin envelopes and then both envelopes can be placed into the same larger envelope Recommendations for Collection and Packing of Biological Evidence To minimize the chance of cross transfer of adhering evidence; different No! clothing items should NOT be packaged in the same container No! Recommendations for Handling Biological Evidence Attempt to insure that anything that contacts biological samples during collection is free of anything that might contain human DNA A- Work on clean surfaces B- Wear gloves and change when necessary Packaging a Wet Bloodstain On a Swab After samples are dried, package the bloodstain sample and the control into separate coin envelopes How NOT to Package a Wet Bloodstain Do not use any packaging device that limits air exchange Biological samples will deteriorate if it takes too long for them to dry NO !!!!!! Packaging of Dry Bloodstain Once the sample is dried it can be safely placed into a paper envelope and sealed Packaging of Blood wearing Cloths Attempt to allow bloodstains to dry as much as possible Place clothing onto a piece of clean paper Packaging of Blood wearing Cloths Place paper between stained areas so as to prevent stain transfer Packaging of Blood wearing Cloths Place paper between stained areas so as to prevent stain transfer Packaging of Blood wearing Cloths Seal and dated package with bloody loaded shirt Insert paper package into larger paper bag This is NOT the proper way to package a bloody knife Although paper is good packaging for bloodstained evidence This knife needs to be immobilized because… This is NOT the proper way to package a bloody knife It can easily pierce the paper envelope and endanger any one who handles this evidence In addition, blood from the blade can be easily lost How to Properly Package a Bloody Knife Use a cardboard box (not airtight) Immobilize knife to protect both personnel & the blood sample on blade Packaging of Trace Evidence Trace evidence is small evidence which can be easily lost Examples of trace evidence: 1- Hairs 2 Glass fragments 3 Paint flakes 4 Fibers Packaging of Trace Evidence If it is necessary to remove and package trace evidence, its nature and location must be documented before the evidence is altered Packaging of Trace Evidence Items must be visually examined and trace evidence identified A- Trace evidence can be removed with tweezers and placed into appropriate packaging B- Trace evidence can also be removed with tape lifts Packaging must be appropriately sized & designed so that this small evidence cannot fall out of the container Glass Fragments Glass fragments are small and can be lost from poorly sealed envelopes Glass Fragments Deposited into Large Envelope Small glass fragments can be lost from poorly sealed envelopes These fragments need to be packaged into a bindle before being placed into envelope First Step: Placing Glass Evidence into a Bindle The glass is collected and placed into a paper bindle The bindle is then sealed before it is inserted into an envelope Packaging of Paint Fragments Bindles can also be used to package Paint fragments Packaging Paint Fragments Rigid boxes can then be used to hold paper bindle with Fragile paint fragments Box is then placed into paper evidence envelope Information Needed on Evidence Container Name of item and each individual who had custody of the item Dates and Time of Collection Agency Number, Case Number, Item Number and Type of crime Name of victim and suspect Brief description of item Each item should be packaged separately in a clean container that is specific for the item and type of evidence Note #1 “Remember, any time evidence is moved, it is altered. Therefore, proper methods of scene documentation, collection and preservation are necessary so the scene and events leading to the crime can be accurately reconstructed” Chain of Custody Chain of Custody is the documentation of possession of property or evidence which allows one to trace the individuals who have custody of said evidence, the time and date of transfer of said evidence and where it was secured or stored. It provides accountability and insures that the evidence has not been tampered with or substituted. Essential Information Case Number Item Number Item Description Date and Time of Transfer Written and signed name of person (include agency) of individual releasing and receiving information In last few decades, physical evidence has become important as it independently and objectively connects the suspect or victim with the crime. The admissibility of the evidence in the court of law is affected by the collection and preservation of the evidence. Many important cases have been affected due to improper collection and preservation of the evidence. If the evidence is not properly documented, its origin can be questioned. Admissibility challenges: 1. Procedural & technical issues 2. Contamination 3. Analytical issues 4. Results interpretation 5. Statistics Avoid contamination. Ensure that specimens are not contaminated by other materials. Wear gloves at all times. Modern DNA assay systems are very sensitive and may detect small amounts of extraneous material. Collect early. Try to collect forensic specimens as soon as possible. The likelihood of collecting evidentiary material decreases with the passing of time. Ideally, specimens should be collected within 24 hours of the assault; after 72 hours, yields are reduced considerably. Handle appropriately. Ensure that specimens are packed, stored and transported correctly. Analytical laboratories should be able to provide guidance on special requirements for specimen handling and storage. As a general rule, fluids should be refrigerated; anything else should be kept dry. Label accurately. All specimens must be clearly labelled with the patient’s name and date of birth, the health worker’s name, the type of specimen, and the date and time of collection. Ensure security. Specimens should be packed to ensure that they are secure and tamper proof. Only authorized people should be entrusted with specimens. Maintain continuity. Once a specimen has been collected, its subsequent handling should be recorded. Details of the transfer of the specimen between individuals should also be recorded. It is advisable to check with local authorities regarding the protocols for the recording of such information. Document collection. It is good practice to compile an itemized list in the patient’s medical notes or reports of all specimens collected and details of when, and to whom, they were transferred. Use only sterile, cotton swabs (or swabs recommended by your laboratory). • Do not place the swabs in medium as this will result in bacterial overgrowth and destruction of the material collected by the swab. Swabs placed in medium can only be used for the collection of bacteriological specimens. • Moisten swabs with sterile water or saline when collecting material from dry surfaces (e.g. skin, anus). • If microscopy is going to be performed (e.g. to check for the presence of spermatozoa), a microscope slide should be prepared. Label slide and after collecting the swab, rotate the tip of the swab on the slide. Both swab and slide should be sent to the laboratory for analysis. • All swabs and slides should be dried before sealing in appropriate transport containers. A hole or cut may be made in the swab sheath to allow drying to continue. All evidence packages must be labeled or tagged. The label or tag must contain the following information: 1 Complaint number. 2 Date. 3 Recovering/packaging individuals name. 4 Description of exhibits including make, model, and serial number, if any. COLLECTION OF BLOOD AND/OR OTHER BODY FLUIDS 1. Appropriate safety measures, Protective gloves will be worn, and depending on the nature of the evidence and the collection scene, protective clothing, face masks, eye-wear, etc. will be worn. 2. Fresh (wet) blood will be collected either on sterile swabs or on sterile gauze and must be air dried before packaging. 3. Wet swabs or gauze may be transported to HPD in a plastic container prior to air drying. 4. After thoroughly drying, the item will be packaged in brown wrapping paper, paper bags, or similar packaging. Packaging will be marked, sealed, and tagged or labeled. 5. When collecting dry blood not on fabrics, the entire object that contains the blood stain should be submitted whenever possible. 6. When the blood stain is located on a wall, floor, or other object that cannot be submitted, then a) scrape several large flakes into a plastic vial. b) When the stain is small, collect the stain on 2-4 sterile cotton tip swabs. 7. Body tissue must be collected and placed in a sterile vial in sterile distilled water. 8. Any bio-hazardous material (e.g., blood soaked clothing) that needs to be dried will be placed in a biohazard drying chamber. Detection and Visualisation of Latent Fingerprints • Use of fingerprint powders. • These can be coloured (black, white or metallic), fluorescent or magnetic materials that are finely ground. • They are brushed slightly over a suspected print. • This produces a contrast between the background and the now-visible print. What does this imply? • Photograph this! • Magnetic powders work best on coated or shiny surfaces. …cont’d. • Powders are applied with a soft fiberglass brush with long, fine bristles. • These bristles are usually made of camel hair. • Brush is dipped into the powder and gently applied to the fingerprint with a light touch. • Magnetic powders require a magnetic applicator. Fingerprint Powders Black Powder Application of black powder and subsequent magnification Fingerprint Powders … cont’d. Fluorescent Fingerprint Kit Magnetic Fingerprint Powder Note the applicator! Chemical Methods of Development of Latent Fingerprints 1. • • • • • Iodine Fumigation Iodine is a solid at room temperature. What does It sublimes. this mean? When iodine vapours are exposed to fingerprint residues, they react to form a reddish image of the fingerprint. This image is temporary. Visualised image must be photographed. Development of Latent Fingerprints by Iodin Fumigation Fingerprint developed with iodine, the right part is fixed with benzoflavone. A questioned document being sprayed with silver nitrate. 3. Ninhydrin Method • Used for developing fingerprints on porous surfaces like paper. • Ninhydrin + amino acid residues in the fingerprints purple coloured compound. • The compound is called Ruhemann’s Purple. Fingerprint development using ninhydrin 4. Cyanoacrylate (Superglue) Fuming What is serendipity? • Serendipitous discovery! • Japanese scientists testing a cyanoacylate ester to make a new glue. • The ester was heated in the fume hood; left for a while. • After some time, the glassware in the hood had visible fingerprints. What type of fingerprints are initially formed on glassware? • Used these days to fume small, confined areas. • Prints formed are permanent! UNIVERSAL PRECAUTIONS The U.S. Occupational Safety and Health Administration (OSHA) developed universal precautions to protect workers from exposure to human blood or other potentially infectious materials. It is not possible to determine if every bodily fluid or stain collected from crime scenes is contaminated with a bloodborne pathogen; therefore, all bodily fluids and tissues are presumed to be contaminated. When individuals handle any type of biological evidence, procedures need to be in place to reduce or eliminate the risk of exposure to bloodborne pathogens that can transmit disease (OSHA 2012). BIOLOGICAL EVIDENCE DISPOSITION Disposition is the ongoing process of determining what to do with evidence in a case. The process may entail retention and disposal, destruction, auction, diversion to governmental agency use, or return to owner. ITEMS • Protective Personal Equipment (PPE): These include: - Gloves (latex, nitrile, cotton) - Facemasks (and/or respirators designed to protect against blood-borne viruses and dust) - Hair nets - Plastic overshoes - One-piece disposable suit - Safety spectacles or goggles • Sterile sealed swabs • Disposable sterile tweezers/forceps • Selection of plastic tubes and pots • Sterile disposable plastic pipettes • Disposable sterile scalpels or razor blades • Biological hazard bags and sharp bins • Selection of sizes of tamper evidence or polythene bags • Selection of sizes of brown paper sacks • Selection of sizes of cardboard boxes (flat pack) • Scissors • Sellotape • Stapler and staples • Evidence tape and tags • Scene of Crime barrier tape • Small identification labels used during photography • Pens and indelible markers to write on clear plastics • Ruler and tape measure • Plain paper (A4 and A3) • Thermometer • Magnifying glass • Torch • Fingerprint brushes and selection of fingerprint powders • Lifting tape with acetate sheet • Alternative light source (ALS) • Digital and video camera • Clipboard • Crime Scene Investigation forms and necessary laboratory documents REAGENTS • Distilled or deionized water (sterile) • Ethanol for cleaning • Bleach • Reagents for presumptive testing of biological stains • Fingerprint enhancement reagents Procedures for the Collection and Preservation of Biological Evidence 1. Double Swabbing Method Use the double swabbing method to collect dry evidence from medium to large non-porous items such as metal, glass or plastic 2. Cutting Method When on an SOC, use this method for stains found on large and porous objects (e.g. fitted carpets, sofas). 3. Scraping Method Use this method to recover dry material from soft and porous items. 4. Tape Lifting Method The following method can be used to collect samples of small dry stains from non-absorbent surfaces. Used for powdered fingerprints or areas suspected of containing touch DNA. 5. Picking Method The following method can be used for the collection of solid biological material such as hair, tissue or bone fragments 6.
