Science of Crime Scenes Chapter 8.2 Science of Crime Scenes

Terrorist Crime Scenes Science of Crime Scenes

Science of Crime Scenes

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

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

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

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

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

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