Biological Evidence Lecture Notes PDF

FRSC3100 Biological Evidence Dr. Sanela Martic 1  Importance of body fluids Body fluid and body tissue identification are important in forensic science as they can provide key evidence in a criminal investigation and may assist the court in rea...

FRSC3100 Biological Evidence Dr. Sanela Martic 1  Importance of body fluids Body fluid and body tissue identification are important in forensic science as they can provide key evidence in a criminal investigation and may assist the court in reaching conclusions. Establishing a link between identifying the fluid or tissue and the DNA profile adds further weight to this evidence. https://forensiccoe.org/emerging-methods-body-fluid- analysis/ 2  What are key values of biological fluids? - Exclusion of suspect - Source of DNA - Linking victim + suspect - Identification of unknown victims - Sexual assault cases https://wires.onlinelibrary.wiley.com /doi/epdf/10.1002/wfs2.1407?saml_ referrer= 3  Value of biological fluids Body fluid identification can: support activity-level information in cases, assign relevance to DNA profiles resulting from stains, elucidate event timelines, and support scene reconstruction https://wires.onlinelibrary.wiley.com /doi/epdf/10.1002/wfs2.1407?saml_ referrer= 4  Locating Biological Forensic Evidence (1) to find traces related to the alleged crime which can then be collected and from which the identity of the perpetrator may be revealed by further testing; (2) to contextualize the traces to provide information about what activities may have taken place. This can be done at the scene, where time is limited, using techniques that are mostly presumptive and visual in nature, or in a forensic laboratory (using samples and items collected at the scene) where more detailed analysis is possible. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 5 1/  Locating Biological Forensic Evidence (3) to assess the cellular content of the primary stain in relation to the DNA recovered from the evidentiary sample as some fluids have very high cellular content (for example nasal secretion), whilst others contain much fewer cells (for instance urine) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 6 1/  Locating Biological Forensic Evidence (4) to assess whether the body fluid involved is likely to occur in what is suggested to be the primary location. -intimate body fluids (vaginal cellular material, menstrual secretion, semen) can be found in underpants of the wearer, but are less expected on hands or touched items. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 7 1/  Locating Biological Forensic Evidence (4) to assess whether the body fluid involved is likely to occur in what is suggested to be the primary location. Saliva and nasal secretion, on the other hand, can reside on hands or items, and blood could occur when people have (small) wounds. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 8 1/  Locating Biological Forensic Evidence (4) to assess whether the body fluid involved is likely to occur in what is suggested to be the primary location. Organ tissues (for instance, CNS (central nervous system), heart, or adipose tissue), on the other hand, are not expected on hands or on items. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 9 1/  Contextualizing Evidentiary Traces Activity-level evaluations or contextualizing the scene: - Type of bodily fluid or tissue - Pattern of bodily fluid or tissue - Location - Amount https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 10 1/ Body fluids in courts Cases come to court in which the presence of cellular material of a person is not disputed but the activity that caused the deposition is. The debate then centers around the question ‘how did it get there’? 11  Activity-level evaluations Weigh the likelihood of the forensic evidence under: -scenario 1 (hypothesis 1; H1, also known as prosecution scenario) -scenario 2 (hypothesis 2; H2, also known as defense scenario). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 12 1/  Hypothesis 1 The ‘findings’ in the case can relate to cellular material matching victim or suspect which under H1 is indicative of an offensive activity ○ blood matching the victim on the blade of a knife indicative of the victim being stabbed; ○ cellular material matching the suspect on the handle of a knife supporting the proposition that the suspect carried out the stabbing. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 13 1/  Hypothesis 2 This questioned cellular material on the evidentiary item may result from a number of scenarios: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 14 1/  Hypothesis 2 (1) the cellular material was deposited not during the offense but at an earlier or later time (the suspect did not stab but picked up the knife after the stabbing); https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 15 1/  Hypothesis 2 (2) the cellular material was not deposited by direct contact but was the result of secondary (or tertiary or further) transfer (the suspect shook hands with the real perpetrator who then handled the knife in the stabbing); https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 16 1/  Hypothesis 2 (3) the item on which the cellular material was deposited belongs to the suspect but was used in the offense by another person (the knife (owned by the suspect who uses it to cut food) was handled by the real perpetrator in the stabbing); https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 17 1/  Hypothesis 2 (4) the cellular material was deposited on the knife in a different way (the victim fell into the knife). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC861762 18 1/  Body fluids - analysis https://www.ojp.gov/pdffiles1/nij/gra 19 nts/256087.pdf  Chemical Sprays for Blood Luminol and the more user- friendly, luminol-derived Bluestar (Bluestar Forensic, Monaco) reagent, are often used to detect haemoglobin and its derivatives resulting in a blue fluorescence which is captured by photography. https://www.sciencephoto.com/media/860254/view/lumi nol-used-to-detect-blood-2013 https://www.chemistryworld.com/podcasts/luminol/7272 20.article  Chemical Sprays for Blood Fluorescence is more Blood dilutions sensitive then naked-eye observation. The area without bloodstain could also be emissive after sprayed with luminol working solution, which could be troublesome for CSI to collect the bloodstain pattern for further analysis. Robust Serum Albumin-Responsive AIEgen Enables Latent Bloodstain Visualization in High Resolution and Reliability for Crime Scene Investigation 21 Demonstration of bloodstain visualization in mock crime scenes: retrieval of bloodstain patterns (a) pristine blood on a glass substrate (silica gel on glass plate was used as the surface). The blood was then rinsed with water and aged for 14 d. Then, the glass surface was sprayed with fluorescent reagent and photos were taken under (b) ambient light or c) 365 nm UV irradiation. Robust Serum Albumin-Responsive AIEgen Enables Chemical Latent Bloodstain Visualization in High Resolution and Reliability for Crime Scene Investigation | ACS Applied Sprays for Materials & Interfaces Blood 22  ambient light 365 nm UV irradiation Demonstration of bloodstain visualization in mock crime scenes: retrieval of bloodstain patterns (a) pristine blood on a glass substrate (silica gel on glass plate was used as the surface). The blood was then rinsed with water and aged for 14 d. Then, the glass surface was sprayed with fluorescent reagent and photos were taken under (b) ambient light or c) 365 nm UV irradiation. Robust Serum Albumin-Responsive AIEgen Enables Chemical Latent Bloodstain Visualization in High Resolution and Reliability for Crime Scene Investigation | ACS Applied Sprays for Materials & Interfaces Blood 23  Chemical Sprays for Blood day light 365 nm UV irradiation Impact bloodstain formed by splashing blood diluted by a factor of 100 onto a porous Robust Serum Albumin-Responsive AIEgen Enables surface. Latent Bloodstain Visualization in High Resolution and Reliability for Crime Scene Investigation | ACS Applied Materials & Interfaces 24  Chemical Sprays for Blood 365 nm UV day light irradiation Impact bloodstain formed by splashing blood diluted by a factor of 100 onto a porous Robust Serum Albumin-Responsive AIEgen Enables surface. The cellulose paper was then Latent Bloodstain Visualization in High Resolution and Reliability for Crime Scene Investigation | ACS Applied sprayed with a solution of fluorophore. Materials & Interfaces 25  Chemical Sprays for Blood Disadvantages: -the luminescence produced can be faint and short-lived, -in the case of luminol the visualization must be carried out in near darkness https://www.sciencephoto.com/media/860254/view/lumi nol-used-to-detect-blood-2013 https://www.chemistryworld.com/podcasts/luminol/7272 26.article Blood Pattern Analysis 27 The International Association of Bloodstain Pattern Analysts is an organization of forensic experts specializing in the science of bloodstain pattern analysis. https://www.iabpa.org/ 28 What can BPA provide? - Direction of blood and force - Angle of impact - Type of wound - Distance - Force (nature of object) - Movement of victim + suspect - Number of blows - Sequence of events - Handedness (which hand was used) 29 Bloodstain pattern at crime scene- Seatle 2002: the victim had his right hand severed and died of 234 sharp-force injuries of the head, neck, trunk, and extremities LINK 30 BPA-Directionality During training, investigators typically produce similar stains by dropping blood onto cards that are set at angles ranging from 10 to 90 degrees impact angle. LINK 31  BPA- challenges: Accuracy and reproducibility of conclusions by forensic bloodstain pattern analysts https://www.sciencedirect.com/science/arti cle/pii/S0379073821001766 32  BPA- challenges: Accuracy and reproducibility of conclusions by forensic bloodstain pattern analysts - 75 BPA analysts - 192 bloodstain patterns - Known samples - 11.2% of the analysts’ responses were erroneous - 7.8 of the analysts’ responses contradicted other analysts https://www.sciencedirect.com/science/arti cle/pii/S0379073821001766 33 Body fluids – practitioners – lab setting For each bodily fluid, results of tests may be reported as: “detected”, “suggested”, “inconclusive”, or “not detected”. 34 35 Est.1903 Kastle-Meyer blood test reagents are deleterious to DNA https://www.sciencedirect.com/science/article/pii/S0379073817304073?via%3Dihub https://www.flinnsci.com/kastle-meyer-reagent-100-ml-forensic-test/ap7555/ 36 KM test was Negative positive in the KM test absence of visible blood 37 38 39  40 https://www.sciencedirect.com/science/article/abs/pii/S1355030620303087 N/A Negative for Phadebas Do not permit test confirmation (not confirmatory) ORDER Matters: Blood swab done first, the saliva test done second 41 ORDER Matters: Blood swab done first, the saliva test done second 42  - Present in high amount in semen - Purple = positive Evidence persistence: Semen evidence can last ~7 days 43 Evidence persistence: Semen evidence can last ~7 days 44 Evidence persistence: Semen evidence can last ~7 days 45  Body fluids - Challenges Lack of sensitivity or selectivity of some methods Scene vs. Lab uses – method selection Only single body fluid at a time can be measured. The investigator needs to decide which test to perform based on the fluid that is most likely present. The analyst needs to decide on the order of tests. Methods may be destructive!!! - DNA compromised etc. https://www.sciencedirect.com/scie nce/article/abs/pii/S037907380900 0826?via%3Dihub 46  What are some challenges associated with DNA evidence? https://www.nist.gov/feature-stories/dna-mixtures-forensic-science-explainer 47  Thirty years of DNA forensics: How DNA has revolutionized criminal investigations DNA profiling methods have become faster, more sensitive, and more user-friendly since the first murderer was caught with help from genetic evidence 2017(C&EN News Volume 95, Issue 37) 48  DNA evidence in the news Sharron Prior, 16, was last seen March 29, 1975. A new DNA tool helped crack a Montreal cold case. It could help solve others For decades, nobody knew who killed Sharron Prior DNA taken from the remains of Franklin They also had some clothing Romine, exhumed in West Virginia in left at the crime scene that early May, proved to be a perfect match would later provide traces of for the DNA left at the scene by Sharron's the killer's DNA. killer. https://www.cbc.ca/news/canada/montreal/prior-cold-case-dna-new-tool-1.6856007 49 DNA evidence-transfer The concepts of primary, secondary and tertiary DNA transfer have been widely reported in scientific journals and revealed in cases of wrongful conviction Defence counsel proposed that Prosecution argued that suspect’s DNA was transferred to the the DNA was deposited item by a co-accused, after the pair on the item directly by shook hands hours before the murder suspect during the attack (secondary transfer). (primary transfer). How the DNA was deposited could not be established beyond reasonable doubt 50  DNA evidence-stability Persistence and stability of DNA on various surfaces Environmental factors degrade DNA Degraded DNA is an issue Properly stored DNA will last a long time (decades! "Innocence Project") DNA degradation is a process by which DNA breaks down into smaller fragments. Environmental factors such as sunlight, heat, and humidity can increase the rate of degradation. DNA samples that are subjected to environmental factors that promote degradation can pose challenges for data interpretation. NIJ link 51  DNA evidence-stability degradation can be easily identified because the peak heights exhibit a downward the STR regions of the slope across the DNA molecule can be electropherogram fractured reduced the peak heights, If the STRs do not stay making them too low to be intact, amplification of distinguished from these regions will not background noise in the data be successful Partial profile 52 DNA evidence-mixtures DNA mixture (2 or more profiles) A murder weapon may have 3 DNA profiles (1 suspect + 2 victims) The mixed profile DNA can be run against a suspect DNA (reference) to help identify them The mixed profile DNA can be compared to another mixed profile Mixed and partial profiles – challenges with DNA database STRmix – DNA mixture characterization software package 53  DNA evidence-mixture Study Subjectivity and bias in forensic DNA mixture interpretation - 17 DNA experts - 1/17 experts gave same conclusion as the original analyst - 16/17 experts had different conclusions as the original analyst (e.g. exclude, inconclusive) DNA mixture interpretation has subjective elements and may be susceptible to bias and other contextual influences. https://www.sciencedirect.com/science/article/pii/S1355030611000967?via%3Dihub 54 DNA Database As of 2018, there are currently 13-15 million profiles in CODIS. DNA database analysis may take several days to get CODIS regulated the use of DNA samples in results the federal database by mandating that samples be processed through compliance with quality assurance standards, that they undergo an external audit, and that DNA Profile may not be in the laboratories submitting DNA records the database are accredited through a non-profit, nationally recognized association engaged in forensic science. 55  DNA profiling in Canada linking crimes together where there are no suspects National DNA Data Bank helping identify suspects eliminating suspects where there is no match between a crime scene DNA profile and a convicted offender's DNA The National DNA Data profile Bank (NDDB) maintains determining if a serial offender is a collection of more involved then half a million DNA identifying a victim of a crime profiles. identifying human remains and assisting investigators, coroners and medical examiners to find missing persons 56 https://www.rcmp-grc.gc.ca/en/forensics/national-dna-data-bank  DNA profiling in Canada Offence Total National DNA Data Bank - Murder 5,729 Offender hits by case type Sexual assault 8,459 Issued on Oct 15th 2024 Type of biological sample Attempted murder 1,724 Robbery (armed) 9,091 Breaking and 35,232 entering Assault 6,767 Other 18,429 Total 85,431 57 https://www.rcmp-grc.gc.ca/en/forensics/national-dna-data-bank  Is it possible to do DNA profiling at the police station? The U.S. government’s Rapid DNA program aims to develop integrated systems that work The Rapid DNA Act of 2017, without human intervention so which would allow DNA that nontechnical personnel profiles generated outside could use them in police stations accredited labs to be used to to query databases. search CODIS, was passed by Congress and signed into law. 2017(C&EN News Volume 95, Issue 37) 58  DNA profiling at the police station? Under this law, in states with laws allowing arrestee testing, police can take cheek swabs at the time of booking. “You put a swab in. In After processing, the CODIS- 90 to 100 minutes, you eligible DNA profile is generate a DNA profile,” automatically sent to the FBI’s CODIS database. If there is a “hit”, an automatic notification is made. https://www.ande.com/booking 2017(C&EN News Volume 95, Issue 37) 59 CanLii case 1: R. v. Mercer, 2007 BCSC 672 Mr. Mercer, broke into Mrs. Larochelle’s home at 119 Irwin Street, in Nanaimo, British Columbia, in the early evening hours of June 2, 2002, intending to steal items from her home. In the course of this break and enter, the Accused came upon Mrs. Larochelle in her bed and there assaulted her. The assault, consisting of numerous blows to her head and face, continued in the living room, where Mrs. Larochelle was killed. Which evidence was considered? LINK: R. v. Mercer 2007 BCSC 672 60  CanLii case 1: R. v. Mercer, 2007 BCSC 672 About 30 cm from Mrs. Larochelle’s head, as she was An expert in spatter pattern found, are two obvious bloody analysis, testified that the partial foot prints. sandal must have been in contact with liquid and The police matched these foot congealed blood to have left prints to Mr. Mercer’s sandals. this print on the carpet. the only source of liquid or congealed blood was Mrs. Larochelle’s head, and that the sandal was therefore used to kick her and cause her death https://www.canlii.org/en/bc/bcsc/doc/2007/2007bcsc672/2007bcsc672.html?resultId=6689924534704818a9eab5fa2dc5679d&searchId=2024-10- 28T15%3A07%3A00%3A152%2Fc16ef5548b194e8f86f73ca4bceecd25&searchUrlHash=&offset=2171&highlightEdited=true CanLii case 1: R. v. Mercer, 2007 BCSC 672 After his arrest, Mr. Mercer’s t-shirt was seized from his backpack. There were several small transfer stains later identified as blood on the t- shirt. Some of the blood was identified as Mrs. Larochelle’s blood, some Mr. Mercer’s. Blood found on the upper left sleeve was contributed to by three individuals. Testing could not exclude Mrs. Larochelle and the Accused as contributing to the sample but a third unknown individual, either male or female, also contributed to the stain on the left upper sleeve. LINK: R. v. Mercer 2007 BCSC 672 62  CanLii case 1: R. v. Mercer, 2007 BCSC 672 Suspect's sock has congealed blood on it. Dr. Gray testified as follows: Q. Hypothetically, if a person was wearing sandals and socks when they kicked this woman, wouldn’t you expect to see some on the toes? A. You would expect to see some blood, yes. Q. If there was no blood on the toes of the person wearing the sandals, that would give much more support to the theory that person isn’t the one that kicked this woman like that? A. That is a difficult question to answer but in general terms, I agree with you. https://www.canlii.org/en/bc/bcsc/doc/2007/2007bcsc672/2007bcsc672.html?resultId=6689924534704818a9eab5fa2dc5679d&searchId=2024-10- 28T15%3A07%3A00%3A152%2Fc16ef5548b194e8f86f73ca4bceecd25&searchUrlHash=&offset=2171&highlightEdited=true  CanLii case 2: R. v. Khan, 1990 CanLII 77 (SCC), 2 SCR 531 On March 26, 1985, Mrs. O. Dr. Khan and T. were alone in When the mother rejoined and her daughter T., who was 3 his private office for a period of T., she noticed the child 1/2, attended at the office of five to seven minutes while the picking at a wet spot on her their family doctor, Dr. Khan for mother undressed and put on a sleeve. a general examination of the hospital gown. mother and a routine immunization of T. T.'s jogging suit was examined and the spot Appellant, was charged with on the sleeve was determined to have been sexually assaulting a 3 1/2 produced by a deposit of semen and, in some areas, a mixture of semen and saliva that had year-old girl. soaked through the fabric before it dried. https://www.canlii.org/en/ca/scc/doc/1990/1990canlii77/1990canlii77.html?resultId=4f18e13ebd87443f89638d7572818b62&searchId=2024-10- 28T14:58:06:044/8c55c4b350e0401fb2283638901e27cf&searchUrlHash=AAAAAQAFc2VtZW4AAAAAAQ 64