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Disaster at the Daisys’

The Analysis of Forensic Evidence


Kimberly S. Farah
Applied Forensic Science
Lasell College


This directed case study was written to help students understand both organic and inorganic analysis of forensic evidence. It tells the story of a fire at the home of Mr. and Mrs. Daisy who are found deceased on the property, both with gunshot wounds. Students assume the role of forensic investigators as they attempt to determine whether the gunpowder pattern evidence points to homicide or suicide. A series of questions guides students through an investigation of pattern evidence and accelerants so that they can develop a hypothesis about the crime. Students must also determine the instrumental methods of analysis needed for the analysis of evidence. This case study was designed for a forensic science course for non-science majors, but could also be used at the high school level or adapted for an instrumental methods course or an organic chemistry course.

  • Use gunpowder residue evidence as a basis for determining the approximate distance from which a shot was fired.
  • Identify the types of elements that are typically found in gunshot residue.
  • Differentiate between destructive and non-destructive analytical methods.
  • Understand the significance of pattern evidence in arson investigations.
  • Differentiate between types of accelerants.
  • Understand how flammable residue is analyzed.
Keywords: Instrumental analysis; gas chromatography; headspace analysis; solid phase extraction; gunpowder residue; criminal investigation; forensic investigation; forensic analysis; arson
Topical Area: N/A
Educational Level: High school, Undergraduate lower division, Undergraduate upper division
Formats: PDF
Type/Method: Directed
Language: English
Subject Headings: Forensic Science   Chemistry (General)   Analytical Chemistry   Organic Chemistry  
Date Posted: 1/23/2019
Date Modified: N/A
Copyright: Copyright held by the National Center for Case Study Teaching in Science, University at Buffalo, State University of New York. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

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The following video(s) are recommended for use in association with this case study.

  Gas Chromatography GC
Demonstration of gas chromatography using a flame ionisation detector (FID) with a brief mention of gas chromatography mass spectrometry (GCMS). Running time: 5:16 min. Produced by Royal Society of Chemistry, 2008.

  Atomic Absorption Spectrometer
Demonstration of the standard operating procedure for the Varian Spectra Atomic Absorption Spectrometer. Running time: 10:28 min. Produced Gary Mabbott, 2016.

  Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES)
Demonstration of ICP-OES. Running time: 4:03 min. Produced by Virtual Soil Science Learning Resources, 2014.

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