1. Science of Crime Scenes
Chapter 8.2
Science of Crime Scenes

2. Terrorist Crime Scenes
Science of Crime Scenes

3. Science of Crime Scenes

4. Varied methods and various goals
Shootings
Bombings
Explosions
Poisons
Nerve agents
Military-grade weapons
Improvised explosive devices (IED)
Science of Crime Scenes

5. Science of Crime Scenes
Bombing scenes
same objective as at any other investigation: to gather physical evidence that will assist the trier of fact, who will successfully prosecute the suspect if he or she is responsible for the explosion
The forensic scientist at the scene will make observations and collect evidence that will attempt to later do the following
Determine the explosive used
Determine sources of IED components
Compare physical evidence from the crime scene
Corroborate statements
Link criminal cases
Science of Crime Scenes

6. Improvised explosive devices (IED)
An IED has five components:
a power source (battery)
a switch (trigger)
an initiator (detonator or fuse)
a charge (explosive)
a container (body)
How these come together to cause an explosion is limited only by the ingenuity of the bomb maker
Many commonly available materials, such as fertilizer, gunpowder, and hydrogen peroxide, can be used as explosive materials in IEDs
Science of Crime Scenes

7. Science of Crime Scenes
Common Uses
Common form
Known IED use
High Explosives
Ammonium Nitrate and fuel oil (ANFO)
Mining and blasting
Solid
Oklahoma City bombing
Triacetone Triperoxide (TATP)
No common uses; mixed from other materials
Crystalline solid
2005 bombings in London
Semtex, C-4
Primarily military
Plastic solid
IRA bombings
Ethylene glycol dinitrate(EGDN)
Component of low-freezing dynamite
Liquid
Millennium bomber, intended for LAX
Urea nitrate
Fertilizer
World Trade Center 1993
Low explosive
Smokeless powder
Ammunition
Olympia Park Bombings
Science of Crime Scenes

8. Science of Crime Scenes
Delivery
They may conceal the device in a package that may be in plain sight, hidden or buried, and detonate it remotely.
Bombers may also place the IED in a vehicle (vehicle-borne IED, or VBIED) and park the vehicle alongside the intended target
A suicide bomber may strap an IED to his body and either walk to, or drive a VBIED to, a target area and explode it.
Science of Crime Scenes

9. Post-blast crime scene
The outer perimeter should be drawn by measuring the distance from the point of detonation to the furthest item of evidence, then adding an additional 50% to that distance.
For VBIEDs this perimeter could be up to 1.5 miles in all directions from the blast site.
Before any searching can begin the safety of the search team has to be considered.
There may still be other devices that have not detonated
The area must be thoroughly cleared of any devices.
Science of Crime Scenes