Ballistics 10

Lecture 10

Explosive crime scenes and photography

-       An explosive crime scene is a location where an explosion has occurred or is suspected to occur, involving criminal intent.

-       Types of explosives:

o   Chemical explosives: Substances that undergo rapid chemical reactions, releasing energy and gas (e.g., TNT, RDX, ANFO)

o   Nuclear explosives: Based on nuclear fission or fusion reactions (rarely encountered in typical crime scenes)

o   Mechanical explosives: Devices that release energy through physical means (e.g., compressed gas cylinders)

Importance of proper scene documentation

o   Crucial for investigation

o   Prosecution

o   Prevention of future incidents.

o   It provides a permanent record of the scene

o   Supports forensic analysis

o Helps in reconstructing the event.

Safety considerations

Personal Protective Equipment (PPE)

Risk assessment

Coordination with bomb disposal units

Equipment needed

o   DSLR cameras with various lenses (wide- o angle, macro)

o   Tripods for stability

o   External flashes and lighting equipment

o   Color charts and scale markers

Importance of scale and reference objects

o   Provides size context for evidence

o   Allows for accurate measurements in photo analysis

o ABFO No. 2 scale is commonly used

Documentation techniques

o   Overall shots: Capture the entire scene and its relationship to surroundings

o   Mid-range shots: Show relationships between pieces of evidence

o Close-up shots: Detailed images of specific items of evidence

Infrared and ultraviolet photography

o   Detects residues not visible to the naked eye

o   Can reveal latent evidence such as gunshot residues or accelerants

o   Requires special cameras or filters

3D scanning and photogrammetry

o   Creates accurate 3D models of the crime scene

o   Allows for virtual walkthroughs and precise measurements

o   Useful for court presentations and scene reconstruction

Overall Shots

o   Capture the entire scene and its relationship to surroundings.

o   Use wide-angle lens, consider elevated positions if possible.

o   Include reference points for orientation.

Mid-range Shots

o   Show relationships between pieces of evidence.

o   Capture blast patterns, debris fields.

o   Use standard lens, include scale for size reference.

Close-up Shots

o   Detailed images of specific items of evidence.

o   Use macro lens, include ABFO No. 2 scale.

o   Take photos from multiple angles.

Improvised explosive devices (IEDs)

-       IEDs are homemade bombs constructed and deployed in ways other than in conventional military action. They can be made from conventional military explosives or wholly improvised explosives.

-       Historical context:

o   IEDs have been used in conflicts for centuries, but gained prominence in modern warfare and terrorism from the mid-20th century onwards.

-       Modern prevalence:

o   IEDs are a significant threat in both conflict zones and civilian areas, used by various actors including terrorist groups, insurgents, and lone attackers.

Composition of IEDs

Main charge

Initiator or detonator

Power source

Switch or trigger mechanism

Container or casing

Additional components

• May include shrapnel (nails, ball bearings) to increase lethality, or incendiary materials to cause fires post-explosion.

Types of explosives used in IEDs

-       Military explosives

o   C-4: Plastic explosive, very stable, high detonation velocity

o   TNT: Relatively stable, less powerful than C-4 but widely available

o   RDX: Highly powerful, often used in mixture with other explosives

-       Commercial explosives

o   Dynamite: Nitro-glycerine-based, still used in mining and construction

o   ANFO: Ammonium Nitrate/Fuel Oil mixture, common in large vehicle bombs

-       Homemade explosives:

o   TATP (Triacetone Triperoxide):

§  Highly unstable, used in several terrorist attacks HMTD (Hexamethylene triperoxide diamine): Sensitive to heat and friction

o   Ammonium nitrate-based mixtures:

Made from fertilizers, used in large-scale attacks

Types of IEDs

Vehicle-Borne IEDs (VBIEDs)

Person-Borne IEDs (PBIEDs)

Radio-Controlled IEDs (RCIEDs)

Victim-Operated IEDs (VOIEDs)

Command-Wire IEDs (CWIEDs)

Projectile IEDs

Switches

o   Time switches: From simple kitchen timers to sophisticated electronic timers
• Command switches: Include physical switches, cellphones, and radio controls  

o   Victim-operated switches: Pressure plates, tilt switches, tension release devices

Power sources

o   Batteries: From small watch batteries to car batteries

o   Capacitors: Store electrical charge for instantaneous release

Solar cells: Used in long-term embedded devices

Containers

o   Pipes: Common in pipe bombs, provide fragmentation

o   Pressure cookers: Used in several high-profile attacks, contain fragment seffectively

o   Vehicles: Allow for large payload sand mobility

Electronic devices: Laptops, radios, or toys used for concealment

IED detection and identification

-       Visual indicators: Suspicious wires, unusual odors, out-of-place objects

-       X-ray and imaging technologies: Portable X-ray devices to see inside suspicious packages Explosive detection dogs: Trained to detect a wide range of explosive odors

-       Chemical sensors and trace detectors: Can identify minute quantities of explosive residues

Bomb scene management

-       Establishing a cordon: Inner cordon for EOD work, outer cordon for public safety • Evacuation procedures: Systematic evacuation of at-risk areas
Roles of personnel:
• First responders: Initial scene security and evacuation

•       EOD teams: Render the scene safe, conduct controlled detonations if necessary

•       Forensic personnel: Evidence collection and documentation

•       Documentation protocols: Detailed logs of all activities, photographic and video recording

Pre-blast scenes

-       A pre-blast scene is a location where an explosive device is suspected to be present but has not yet detonated.

-       Importance of early intervention:

o   Prevents loss of life and property damage. Provides an opportunity to collect intact evidence

o   Allows for the study of device construction and terrorist tactics

-       Challenges in identifying potential threats:

o   Distinguishing between genuine threats and false alarms, Time pressure in decision-making
Balancing public safety with minimal disruption

Types of pre-blast scenarios

-       Suspicious package reports:

o   Unattended bags or parcels in public placeso

-       Intelligence-ledoperations

o   Information from informants or surveillance

o   Monitoring of known extremist groups or individuals

-       Interrupted IED manufacturing:

o   Discovery of bomb-making materials or partially assembled devices

o   Often in residential settings or clandestine workshops

o   Packages with unusual characteristics (wires, strange odors)

-       Bomb threats:

o   Phone calls: Often anonymous, may provide details about device or motive

o   Written messages: Letters, emails, or social media posts threatening attacks

Initial response to pre-blast scenes

-       Risk assessment protocols

o   Evaluating credibility of threats

o   Assessing potential impact and collateral damage

o   Determining appropriate response level

o   Establishment of command structure:

o   Incident Command System (ICS) implementation

o   Clear chain of command and communication channels

o   Integration of multiple agencies (law enforcement, fire, EOD)

o   Evacuation procedures and perimeter control:

-       Establishing hot, warm, and cold zones

o   Safe evacuation routes and assembly points

o   Crowd control and public information management

o   Communication with relevant agencies:

o   Coordinating with police, fire departments, and EOD units

o   Notifying hospitals and emergency services

o   Liaison with local government and media relations

Non-invasive investigation methods

-       Visual inspection from safe distance

-       Use of binoculars or zoom cameras

-       Looking for indicators of IEDs (wires, batteries, suspicious packages)

-       Use of robotics and remote-controlled devices:

o   Deployment of bomb disposal robots

o   Use of drones for aerial surveillance

-       Deployment of explosive detection canines:

o   Trained to detect various explosive materials

-       Can cover large areas quickly

-       Application of X-ray and imaging technologies:

-       Portable X-ray devices to examine suspicious objects

-       Thermal imaging to detect heat sources

-       Millimeter wave scanners for concealed objects

Evidence collection in pre-blast scenes

-       Proper PPE for evidence collectors:

-       Bomb suits for close examination

-       Protective clothing to prevent contamination

-       Sampling techniques for trace evidence:

-       Swabbing surfaces for explosive residues

-       Collection of soil or debris samples

-       Collection of intact devices or components:

-       Photographic documentation before moving

-       Use of bomb containers for safe transport

-       Preservation of digital evidence

o   Securing CCTV footage

o   Collecting computers, phones, or other electronic devices

o   Proper handling to maintain data integrity

Chemical analysis of explosive precursors

o   Gas chromatography – mass spectrometry (GC-MS)

o   Ion mobility spectrometry(IMS)

o   Liquid chromatography (LC)

o   Fingerprint and DNA recovery from device components:

o   Superglue fuming for fingerprints on non-porous surfaces

o   DNA swabbing of handled components

o   Digital forensics on recovered electronic items: