Chat with AIExam 14: Arson and Explosives
What would you collect at a crime scene in which an improvised exploded device was detonated? What point of interest would you be sure to examine?
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Answered by Examlex AI CopilotAt a crime scene where an improvised explosive device (IED) was detonated, the collection of evidence would be meticulous and comprehensive, focusing on both the remnants of the device itself and the broader area affected by the explosion. Here are some of the key types of evidence and points of interest that investigators would be sure to examine:
1. **Device Components**: Any fragments of the device, including the container, triggering mechanism, and any unexploded materials. These could help reconstruct the device and identify the method of construction and components used.
2. **Chemical Residues**: Samples of any residues that could indicate the type of explosive material used. This would involve swabbing surfaces for trace chemicals and collecting any unburned powder or material.
3. **Fingerprints and DNA**: Any surfaces that might hold the fingerprints or DNA of the person who assembled or placed the device. This would include any remaining parts of the device, as well as nearby surfaces that the perpetrator might have touched.
4. **Electronic Components**: If the device had an electronic trigger or timer, any surviving circuitry, wiring, or batteries would be collected for analysis.
5. **Shrapnel**: Fragments that were propelled by the explosion, which could include pieces of the device or other materials added to cause additional harm.
6. **Personal Belongings**: Items that may belong to the suspect or victims, which could provide investigative leads or evidence of the suspect's presence at the scene.
7. **Witness Testimony**: Statements from witnesses who might have seen the suspect, suspicious behaviors, or the actual detonation. This could provide context and help piece together the sequence of events.
8. **Surveillance Footage**: Any available video from nearby security cameras or witnesses' mobile phones that could have captured the explosion or the movements of the suspect before and after the event.
9. **Blast Pattern Analysis**: Documentation of the blast effects on surrounding structures and materials, which can help determine the power and composition of the explosive, as well as the point of origin.
10. **Casing and Enclosures**: Any containers or packaging that might have housed the device, which could provide clues about where the components were obtained or how the device was transported.
11. **Documentation and Communication Devices**: Any notes, plans, or electronic devices that could contain information about the planning and execution of the attack.
12. **Biological Evidence**: Blood, tissue, or other biological materials that could be used to identify victims or the perpetrator.
13. **Environmental Samples**: Soil, water, and other environmental samples from the immediate vicinity that might have been altered or contaminated by the explosive materials.
14. **Vehicle Remnants**: If a vehicle was involved in the incident, all parts of it would be carefully examined for evidence.
Investigators would also be sure to document the entire scene comprehensively before and during the collection of evidence, using photography, videography, and sketches to maintain a record of where each piece of evidence was located. The goal is to gather as much information as possible to reconstruct the device, understand the circumstances of the crime, and identify those responsible.
List the evidence that you would seek to collect, either in photographs or in physical evidence, to determine if a fire was intentional.
(31) Answered by Examlex AI CopilotTo determine if a fire was intentional, I would seek to collect the following evidence:
1. Photographs of the fire scene showing any signs of forced entry or evidence of tampering with locks or windows, which could indicate that the fire was deliberately set.
2. Physical evidence such as accelerants, like gasoline or lighter fluid, which may leave behind residue or distinct odors that can be detected and collected for analysis.
3. Photographs of any unusual burn patterns or multiple points of origin, which could suggest that the fire was intentionally set in different locations.
4. Physical evidence of any incendiary devices, such as matches, lighters, or homemade explosives, that may have been used to start the fire.
5. Photographs of any suspicious behavior or individuals near the fire scene before or during the fire, which could provide valuable evidence for investigators.
6. Physical evidence of any previous threats or conflicts related to the property or individuals involved, which could indicate a motive for intentionally setting the fire.
By collecting and analyzing this evidence, investigators can determine if the fire was intentionally set and gather the necessary information to pursue criminal charges if necessary.
A ____ is a chemical explosion in which the reaction front moves through the explosive at greater than 1000 m/s.
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List the evidence that you would seek to collect, either in photographs or in physical evidence, in an IED case.
(43) What chemical technique(s) would be appropriate to use to determine the identity of an accelerant?
(37) An analyst compared a mixture of methyl ethyl ketone, lighter fluid and gasoline to an unknown accelerant from an arson scene. Which of the following techniques would be best for the comparison of the two samples?
(27) Which of the following must the CSI investigate upon arriving at a suspected arson scene?
(39) A liquid burns at the ____ when the temperature is high enough to vaporize it.
(45) The ion mobility spectrophotometer is a ____ test for explosives residues.
(33) For which sample is solid phase microextraction (SPME) often used?
(44) Combustion on the surface of a solid fuel in the absence of heat high enough to pyrolyze the fuel as observed with coals or a cigarette is termed: ____.
(37) What type of packaging container is recommended for arson evidence?
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