Forensic Biology Chapter 1 notes
Forensic Biology Chapter 1 notes BIOL320
Popular in Forensic Biology
Popular in Biology
verified elite notetaker
This 3 page Class Notes was uploaded by Leanna Widhalm on Thursday February 4, 2016. The Class Notes belongs to BIOL320 at University of North Dakota taught by Dr. Ovtchinnikov in Spring 2016. Since its upload, it has received 9 views. For similar materials see Forensic Biology in Biology at University of North Dakota.
Reviews for Forensic Biology Chapter 1 notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/04/16
Chapter 1: Crime Scene Investigation of Biological Evidence 1. Protection of Crime Scene a. Crime scene investigation begins with initial response to scene. Securing and protecting of the crime scene is carried out by the first responding officer to the scene. b. Entry of authorized personnel admitted are documented using a log sheet. Suspects, witnesses, and victims are evacuated from the scene. c. Proper PPE used – face mask/shield, safety eyeglasses, disposable coverall bodysuit, gloves, shoe covers, and hairnet 2. Recognition of Biological Evidence a. Preliminary survey carried out to evaluate potential evidence b. Higher priority for collection of evidence assigned to evidence with probative value to case. i. Corpus delicti – “body of crime.” Refers to the principle that in order for an individual to be convicted, it is necessary to prove the occurrence of a crime. The physical evidence proving that a crime was committed ii. Evidence that can establish connections such as victim-to- perpetrator linkage c. Locard’s exchange principle – theorizes that the cross-transfer of evidence occurs when a perpetrator has any physical contact with an object or another person. d. Modus operandi (MO) – the pattern of characteristics and manner in which a crime is committed 3. Searches a. Search patterns may include grid, line, or zone which depends on the type and size of the scene. b. Searching for biological stains usually utilizes devices such as an alternate light source which produces a single specific wavelength of light or a desired wavelength by using specific filters i. Phenolphthalein/leucomalachite green tests used for detecting blood evidence ii. Minute amounts of blood not visible to naked eye, enhanced by reagents like luminol and fluorescein which emit chemiluminant and fluorescent light upon reacting with certain biological materials c. Portable and field-deployable instruments have been developed that are capable of processing buccal swabs and potentially other evidence to produce a DNA profile on-site. 4. Documentation a. The conditions at a crime scene, including both the individual items of evidence and the overall scene, must be documented to provide vital information for investigators and for the courts. b. Common documentation methods – drawing sketches, photographs and videographs i. Prior to handling evidence, photographs should be taken with different views – overall view of entire scene, medium-range view showing positions and relationships of items, and close-up view showing details of the evidence. ii. Photographs to include a measuring device as scale to accurately depict the sizes of items iii. Photograph log sheet to record the chronological order of crime scene photographs and to note filming conditions and any additional relevant information iv. Written or audio-recorded notes that include case identifier number, identities of investigators, and description of the scene or items v. Any disturbance to evidence to be recorded also. 5. Chain of Custody a. Custody info recorded at each even when evidence is handled or transferred by authorized personnel, each individual who acquires custody of evidence must sign chain of custody document. 6. Collection of Biological Evidence a. Documentation completed, than collection occurs. b. Bloodstain pattern evidence – thoroughly document pattern evidence at crime scene prior to collection. Useful in reconstruction c. Multiple Analysis of Evidence – nondestructive analyses should be carried out first d. Trace evidence – hair/fibers present in bloodstained evidence should be identified and properly collected. e. Control samples – control samples should be collected from a control area f. Size of stain – PCR based forensic DNA techniques are highly sensitive and allow for successful analysis of very small bloodstains. All bloodstains collected at scene g. Wet evidence – air-dried first to prevent degradation of proteins and nucleic acids 7. Marking Evidence a. Necessary for identification purposes, includes investigator’s initials, item number, and case number. 8. Packaging and Transportation a. Protect and preserve evidence, heat/humidity to avoid to prevent biological evidence from degradation during transport b. Evidence from different sources – to prevent the transfer of evidence from different sources, items of evidence should not be grouped in a single package c. Folding of evidence – if large, dry garments should have a piece of clean paper between different parts of the garment to avoid direct contact between the different parts of the garment d. Packing materials – envelopes, bags, and boxes that are made of porous materials such as paper are appropriate for packaging dry biological evidence. Dry, bloodstained evidence should not be sealed in plastic bags or containers that trap moisture e. Liquid evidence – tubes should be placed in plastic bags to prevent leaks in case of accidental breakage. f. Trace evidence – all such evidence should be wrapped in paper with a druggist’s fold. The wrapped trace evidence can be packed in an envelope. g. Evidence properly labeled with description of evidence and sealed with evidence tape i. Initial and date across seal ii. Seal not to be cut and opened, an opening should be created by cutting at an area distal from the existing seal. 9. Final Survey and the Release of the Crime Scene a. Final survey, discussion with all personnel in investigation team should be carried out to thoroughly review all aspects of search b. All documentation completed, evidence collected, packed, documented, and marked c. Photographs of the final condition of scene photographed. d. Once complete, scene is to be released 10.Crime Scene Reconstruction a. Scientific process of determining the sequence of events and actions that occurred prior to, during, and after crime b. Begins with the formulation of questions related to the problems that need to be solved c. Hypothesis construction based on information obtained, which may explain the events and actions involved in a crime d. Hypothesis tested by conducting reconstruction experiments e. Analyze experimental data and draw conclusion f. If results are consistent, theory can be developed that is intended to provide valuable information to the investigation and future prosecution of a case. If inconsistent, alternative hypothesis to be constructed.
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'