Forensics Unit 2 Part 2 Notes

Units in the Crime Scene 

• Forensic Serology
  • Forensic serology is the study of bodily fluids such as blood, semen, breast milk, saliva, etc. It deals with the identification and characterization of biological, evidentiary samples. When these fluids are discovered at the crime scene, forensic serologists can help detectives identify the possible suspects or eliminate certain suspects through DNA analysis of such fluids.
  • We identify the fluid through the antigens and enzymes present In real-life cases, serology can help: 
    • Blood typing (A, B, O) 
    • Characterizing unknown stains 
    • Semen identification for sexual assault cases 
  • Has played a vital role in the innocence project
• Trace Evidence
  • Identifies different types of transferred trace materials that cannot be seen without an unaided eye during a violent crime. This can help link a suspect to the crime scene or another individual. 
  • Examples of trace material: human hair, animal hair, textile fibers and fabric, rope, soil, and glass 
  • Physical contact between a suspect and a victim may result in the transfer of trace materials. 
  • Trace examiners utilize tools such as tweezers, tape and cotton swabs to collect the evidence. It is later securely packaged into evidence bags to be sent to crime laboratories to be analyzed.
• Toxicology
  • Toxicology studies the effects of drugs and chemicals on biological systems. 
  • Can identify the drugs in blood, urine, hair, sweat, or saliva 
  • Toxicology differs from drug chemistry as it is biological and drug chemistry focuses on the physical drug evidence. 
  • Focuses on identifying poisons and drugs in people 
    • Workplace drug testing 
    • Postmortem testing 
    • Doping testing
• Question Documents
  • Questioned documents are documents that are disputed in court for their authenticity, originality or background. These documents usually include signatures, handwriting, or any other suspicious documents that will be reviewed. The process to identify a questioned document can include, handwriting comparisons, fractured/edge cut comparisons or printing process examinations.
• Drug Chemistry
  • Drug chemistry can be used to analyze physical trace evidence found at crime scenes in order to identify unknown substances (by matching them to known substances) and/or the presence of known drugs. 
  • Samples of substances include powders, liquids, and stains. 
  • Drugs are either stored in sealed envelopes or airtight/watertight plastic containers 
  • The difference between drug chemistry and toxicology is that drug chemistry is strictly physical evidence whereas toxicology is more biological. Toxicology focuses more on how the exposure of the substance affects an organism.
• Latent Print
  • A latent print is an impression of the fingers or palms that have been imprinted onto another surface.
  • Using chemical processing units and special equipment, the team (physical examiners, latent print technicians, fingerprint specialists, etc.) develops latent prints. They perform multiple analyses, such as on the friction ridges or comparing the print to a database.
• Forensic Pathology
  • Forensic pathologists are specially trained physicians that determine the cause of death by examination of the cadaver, both internally and externally. They deal with biological evidence - performing autopsies, taking X-rays, and collecting medical evidence (blood, urine, tissue samples) to detect the presence of diseases, injuries, drugs and poisonings. They can also document sexual assault and reconstruct how the victims received their injuries. Major responsibilities of forensic pathologists include identification of the victim, estimating the time and manner of death, and determining the nature of the murder weapon.
• Firearms and toolmarks
  • A firearms and toolmark examiner is a forensic scientist who is an expert in evidence on  firearms, toolmarks, and ballistics. 
    • They look at small marks on bullets and cartridge cases to see if they were generated by a suspect's gun. 
    • By evaluating muzzle blast damage, and the presence or absence of gunpowder patterns surrounding the hole(s) in the item, the range of the weapon can be determined 
    • Items with toolmarks and tools are examined and compared using microscopic identification
• Forensic Entomology
  • Using bugs to help solve crimes 
    • Can be used to determine when a person/animal died based on the stages of bugs found on their body 
    • Can be used to determine what kind of drugs caused a person's death 
    • Can be used to determine where a person died based on what bugs are found on their body
• Arson
  • Arson investigators are responsible for determining the true cause of fires or explosions whether they were accidental or deliberate  (or fire accelerators). This role includes: Responding to and investigating fire scenes Writing reports Working closely with other law enforcement partners Identifying and collecting evidence Enforcing fire safety codes Questions witnesses and uses footage to make conclusions Can testify in court as an expert witness
• DNA
  • DNA analysis is one of the most instrumental tools in crime scene investigations because everyone’s DNA is unique (except for identical twins). DNA can be found in or on the human body, especially hair, blood, urine, etc. DNA can be used to link a suspect to numerous crimes anywhere. DNA on evidence can survive and remain viable (when not affected by other environmental factors) for decades. It can also be used to identify a victim via cross reference of DNA from possible relatives.
• Forensic Odontology
  • Forensic Odontology studies dental evidence left behind at crime scenes. This includes bite marks, or even possible teeth that may fall out during struggle. The age of the perpetrator and even exact identity (suspect or victim) can be concluded from this practice. Sex can be determined through shape and size of molars.This practice is made possible due to the nature of teeth, which can withstand high temperatures and be preserved despite the body’s tissue decomposition. Though, decay and damage of teeth from impacts can alter the likelihood of obtaining a precise conclusion. Teeth can also inhabit other evidence, such as DNA, blood, and saliva.
• Forensic Anthropology
  • Definition- The examination of human skeletal remains for law-enforcement agencies to help, determine the identity of an identified human race, interpret trauma, and estimated time of death through exhumation and gathering o human remains. . It can asses the age, sex, stature, ancestry, and unique features Practices: -Clay or graphic facial reproduction. -Scanning electron microscopy. -Radiographic techniques. -Photo or video superimposition techniques. -Thin-sectioning techniques of bone histology. -The casting of skeletal materials.
• Explosives
  • TEDAC, or the Terrorist Explosive Device Analytics Center, is an agency within the FBI that handles large bombing cases and  teaches smaller organizations how to deal with less high profile bombing cases. These are some of the steps they follow. 
  • Step 1: Make sure bomb is rendered safe. An x-ray can be used to search for bombs. 
  • Step 2: Search for fragments or residue from the bomb that have been left behind (possibly even inside a body). An IMS device can be used to identify the residue. 
  • Step 3: Properly document and package evidence. Robots can be used to take photos of or detonate bomb. 
  • Step 4: Look for fingerprints, DNA, and other identifying factors on evidence that can connect the bomb to a bomber
  • People on the scene: Bomb disposal technician, Evidence custodian, Bomb squad technician 
  • Most common: pipe bomb, Molotov cocktail, improvised explosives
• Digital Forensics
  • Digital forensics is a branch dealing with the recovery, investigation, and analysis of digital evidence from computers and mobile devices. This may range from recovering deleted texts on a phone, to tracing emails from computers, to investigating breaches in server security. The main goal is to preserve the evidence found in its most original form.