Fluent Essays

Respond to one of the following: Option 1: Criminalist Mick is collecting evidence from a fire scene. He gathers about a quart of ash and soot debris from several rooms surrounding the point of origin.  He stores the debris in a new, clean paint can, filled about three-quarters full.  Seeing several pieces of timber he believes may contain accelerant residues, he cuts them and places them in airtight plastic bags.  A short time later a suspect is arrested and Mick searches him for any signs of an igniter or accelerant.  He finds a cigarette lighter on the suspect and seizes it for evidence before turning the suspect over to the police.  What mistakes, if any, did Mick make in collecting the evidence? Option 2: Police discover a badly decomposed body buried in an area where a man disappeared some years ago.  The case was never solved, nor was the victim’s body ever recovered.  As the lead investigator, you suspect the body is that of the missing victim.  What is your main challenge in using DNA to determine whether it is or is not? How would you go about using DNA technology to test your theory? Option 3: Briefly describe what DNA is and its structure. What are the restrictions on base pairings? Option 4: A woman reports being mugged by a masked assailant, whom she scratched on the arm during a struggle.  The victim gives the police a good description of her attacker, but she is not sure whether the assailant was male or female.  Describe the steps and procedures you might use to determine the sex of the attacker. Option 5: The following pieces of evidence were found at separate explosion sites.  For each item, indicate whether the explosion was caused by low or high explosives, and explain your answers:  lead azide residues; nitrocellulose residues; ammonium nitrate residues; scraps of prima-cord; potassium chlorate residues. Option 6: What color test or tests would you run on a suspect ample to test for evidence of each of the following explosives?  Explain your answers:  tetryl; TNT; chlorate; nitrocellulose. Option 7: Matt is collecting evidence from the site of an explosion.  Arriving at the scene, he immediately proceeds to look for the crater caused by the blast.  After finding the crater, he picks through the debris at the site by hand, looking for evidence of detonators or foreign materials.  Matt collects loose soil and debris from the immediate area, placing the smaller bits in paper folded into a druggist fold.  Larger items he stores in plastic bags for transportation to the laboratory.  What mistakes, if any did Matt make in collecting and storing this evidence.  Option 8: Briefly explain the chemistry of an explosion. What is the difference between a low explosive and a high explosive? Option 9: Describe the process of collecting evidence of explosives? Option 10: What is the difference between screening and confirmatory tests?  Why are both needed? What is a taggant? Which countries are presently using them? Option 11: Briefly describe the chemistry of fire. Option 12: Define in detail conduction, radiation, and convection. Option 13: List the characteristics of a fire scene that would indicate the use of accelerants. Option 14: Define in detail antigens, antibodies, antiserum, and agglutination. Option 15: Describe in detail the Luminol, microcrystalline, and precipitin tests for blood. Option 16: Semen is determined by two tests.  List them and explain each in detail. Option 17: Describe the physical evidence to be collected from a rape victim examination and how it is to be collected.  Who is to collect this evidence? Option 18: Police investigating the scene of a sexual assault recover a large blanket that they believe may contain useful physical evidence.  They take it to the laboratory for a test for the presence of semen.  The serologist asks if the investigator knows of anything that might recently have been spilled on the blanket.  The investigator reports that an overturned bowl of grapes and watermelon was found on the scene, as well as broken glass that had contained wine.  The scientist selects and administers the best test for analyzing that blanket.  The blanket shows a positive reaction after three minutes of the completion of the test.  What test was probably used and what was the conclusion?  Explain your answer. Option 19 Criminalist Cathy is collecting evidence from the victim of a sexual assault.  She places a sheet on the floor, asks the victim to disrobe, and places the clothing in a paper bag.  After collecting pubic combings and pubic hair samples, she takes two vaginal swabs, which she allows to air-dry before packaging.  Finally, she collects blood, urine, and scalp hair samples from the victim.  What mistakes, if any, did Cathy make in collecting this evidence? Option 20: In each of the following situations, indicate how you would go about recovering original writing that is not visible to the naked eye. The original words have been obliterated with a different ink than was used to compose the original. The original words have been obliterated by chemical erasure. The original writing was made with fluorescent ink. The original documents have been charred or burned. Option 21: If a file system defines a cluster as six sectors, how many bits of information can be stored on each cluster.  Explain your answer. Option 22: What are SIMs and SD card and why does a mobile device need them? Do all mobile devices have one or both of these? If not, what substitutes?