How are fire scenes different than regular crime scenes for investigators? Fire scenes are entirely different than the regular crime scenes because the evidence of a fire scene was most likely destroyed or burned to ashes. This makes it a little more difficult to piece together the suspect and convict someone of their crimes. While in a regular crime scene the evidence is not burned and there is at least some evidence that will help point to the suspect. What is the blast effect? The blast effect is when a rush of gas from the main part of the bomb site blow outward as high as 7,000 miles per hour. This is shown in second law of Isaac Newton, which states the acceleration of the object will depend on the force that acts on it. What are the two types of high explosives? The two types of high explosives are Primary explosives and Secondary explosives. Primary explosives are easily ignited or detonated and are very sensitive to heat and friction.
Secondary explosives are usually much less sensitive to heat and friction and they typically have to be ignited through the use of other explosive materials. What is a substrate controls? Why is it done? A substrate control is an uncontaminated substance. It is taken to allow forensic scientists to compare the two samples to each other and observe whether a flammable liquid is present. How is the evidence from a fire scene collected? What should be avoided? The evidence from a fire scene is collected from where the fire is believed to have started and any evidence they find.
Any materials collected from a fire scene are put in airtight containers to prevent the evaporation of any flammable liquid evidences. Plastic bags should be avoided in order to prevent a reaction with any flammable liquid that may be left. Critical Thinking Questions What do you think would be the most challenging part of investigating a fire or explosion crime scene? Why? In my opinion, the most challenging part of investigating a fire or explosion crime scene would be moving at a quick pace without any error.
I feel that in an arson situation it would be difficult for me to decide what should be done first because of the risk of the fire starting back up or evidence being lost is very high in these cases. Do you think search warrants should be required for fire scenes? Why or why not? I don’t think that search warrants should be required for fire scenes because the evidence can literally dissipate within days or even hours. It’s important that crime scene officials get to the scene quickly to prevent any further mishap and damages to any of the evidence. In quick paced cases, the time it takes to get a warrant is time that cannot be spared. Do you think more countries should adopt the practice of putting color coded chips in explosive materials? Why or why not? Yes, I do think other countries should use color coded chips because it allows for the material that started the fire to be identified and then they can use it to figure out who bought a certain item recently.
Why do you think crime scenes involving homemade bombs have increased? I think crime scenes involving homemade bombs have increased because it is becoming easier for people to purchase the supplies needed to make homemade bombs and the instructions on how to make is becoming more available with the internet now a day. Why do you think the procedures are different from normal crime scenes to those involving fire and explosions? What benefits or challenges are there because of these different procedures? I think the procedures are different because some of the sites could still be flammable even after the fire has been controlled making the scene more dangerous for the first responders. I think the challenges are finding the area that the fire was started in and finding the evidence because of the ash and soot at the scene.