Handling Procedures
retrieved Feb 11, 2020, https://firearms-examiner.training.nij.gov/
Module 6
Made By: Mariya Dudin

Objectives:

  • Types of Evidence
  • Class and Individual Characteristics
  • Associative Evidence
  • Crime Scene
  • Evidence in the Laboratory

Types of Evidence:

Physical

Biological

Drug

Other

Class and Individual Characteristics

Associative Evidence
contact between...

The Crime Scene

Laboratory Evidence Handling

  • Physical objects (often minute in size)
  • Corroborative evidence
  • Circumstantial evidence

Trace Evidence

  • minute and transient
  • measurable
  • VERY IMPORTANT
  • blood
  • semen
  • saliva
  • bone
  • skin
  • hair

PPE when handling

Touch DNA Evidence

  • A DNA profile may be obtained by swabbing items thought to have been handled by a suspect, even in the absence of visible evidence

Legal and Illegal chemical substances

Integrity - generally stable
Safety - bloodborne pathogens, traps, fire, explosions

Crime scene reconstruction

Questioned documents

Toxicology

Computer crime

Class Characteristics

  • like or consistent with a questioned source
  • Measurable features of an item

Individual Characteristics

  • Marks produced by random imperfections on the surfaces of the tools used to manufacture
  • microscopic level
  • Can be produced on an object by use, abuse, and/or corrosion
  • May be uniquely identifiable with a source

Subclass Characteristics

  • Discernible surface features
  • Produced incidental to manufacture

People

  • blood from physical injury
  • semen from sexual assault

Objects
-fibers left from contact of clothing with objects

People and Objects

  • latent fingerprints left on an object

Value

  • specificity or degree of identity
  • frequency of occurrence
  • persistence of the transferred material
  • likelihood of alternate explanations

Safety

  • priority is to protect life

Protecting the Scene

  • minimize the risk of contamination and loss of evidence
  • access limited
  • Officer placed in charge

Recording the Scene

  • notes: written and audio
  • sketches and diagrams
  • photography: still and video

Chain of Custody
must include:

  • unique identifier
  • item description
  • identity of the person who collected the item
  • time and date
  • location

Firearms Evidence

  • unloaded and placed in a safe condition
  • fired and unfired ammunition should be collected
  • objects with bullet holes should be collected

Toolmark Evidence

  • various techniques to collect
  • strong secure container
  • varying sizes

Evidence Submission

  • Proper Documentation
  • Receipt of Evidence

General Principles

  • Safety
  • Integrity
  • Chain of Custody

Case Tracking Within the Laboratory

  • System in place to keep track of status and overall caseload
  • organized information

Forensic LIMS

  • developed for research
  • used for management purposes
  • keeps track of cases

Goals:

  • Immediately assess the status and progress of a given evidence submission
  • Produce a quick snapshot of the overall current caseload at any time.

Evidence Distribution

Centralized system
laboratory manager or trained individual within the evidence-receiving or evidence-control organization:

  • breaks the seal on the container
  • determines the types of examinations required
  • coordinates the distribution of evidence with the appropriate discipline area for assignment to examiner(s)

Examiner based system
upon breaking the seal on the container, the examiner acts as the hub of the chain of custody within the laboratory and is responsible for:

  • distributing evidence,
  • sequencing examinations
  • identifying significant examinations that were not requested.

Storage

  • Physical plant factors
  • Organizational structure factors

Physical Integrity of Evidence

  • all evidence storage facilities must maintain the physical integrity of the evidence

Controlled Access

  • High Security