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CSI Mexico City

CSI Mexico City. Case No. 892957. Time: between 11.30 and 13.30 Date: 18/10/2010 Scene of the crime: Liverpool Insurgentes Jewellery department Incident: Theft of a $1,000,000 diamond necklace. Case notes. Necklace was removed from display on the main floor for cleaning

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CSI Mexico City

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  1. CSI Mexico City

  2. Case No. 892957 Time: between 11.30 and 13.30 Date: 18/10/2010 Scene of the crime: Liverpool Insurgentes Jewellery department Incident: Theft of a $1,000,000 diamond necklace

  3. Case notes • Necklace was removed from display on the main floor for cleaning • It was locked in the manager´s desk in the employees room between 11.30 and 13.30 • When the manager returned to his desk the lock to his desk drawer had been broken and the necklace was gone!!

  4. Case No: 892957 Evidence No: #7234 Secured: 14.31 18/10/10 Photograph of missing item

  5. Additional notes • Only 3 employees had their break within the time frame the necklace could have been stolen in • The only evidence recovered from the scene of the crime was crumbs of food

  6. Case No: 892957 Evidence No: #7235 Secured: 15.21 18/10/10 Crumbs of food on manager’s desk

  7. Your task this lesson • Identify the source of the crumbs left by the thief • Match your evidence to the lunches of the 3 employees that had their break at the same time as necklace went missing

  8. Testingforsugars Method: Mix small amount of each food sample with distilled water to make a test liquid. 2. To a test tube, add 40 drops of liquid to be tested. 3. If testing more than one liquid, label each test tube with a marker. 4. Add 10 drops of Benedict's solution to each test tube. Carefully heat the test tubes by suspending in a hot water bath at about 40-50 degrees celsius for five minutes. 5. Note any color change. If sugar is present solution will turn green, yellow, or brick-red, depending on sugar concentration.

  9. Testingforstarch Method: 1. Mix small amount of each food sample with distilled water to make a test liquid. 2. To a test tube, add 40 drops of liquid to be tested. 3. If testing more than one liquid, label each test tube with a marker. 4. Add 5 drops of iodine solution to each test tube 5. Note any color change. If starch is present solution will blue/black

  10. Testingforprotein Method: 1. Mix small amount of each food sample with distilled water to make a test liquid. 2. To a test tube, add 40 drops of liquid to be tested. 3. If testing more than one liquid, label each test tube with a marker. 4. Add 10 drops of Biuret’s solution to each test tube 5. Note any color change. If protein is present solution will purple

  11. Testingforlipids • Add 10 drops of ethanol to a few drops of the unknown substance in a test tube 2. Shake well 3. Add 10 drops of distilled water to the test tube 4. A positive result will result in a cloudy white suspension forming at the top of the solution.

  12. Back to the case! • Suspect 1: -only had jelly beans for lunch • Suspect 2 -had plain pasta dressed with olive oil • Suspect 3 -had a ham sandwich What results would you expect to get with each suspect? How will you match your results to the sample from the crime scene?

  13. Resultsfromforensics • Eachgroup has to come up with a possiblesuspectbytheend of theperiod. • Remember – youwillbecalled as anexpertwitnesswhenthis case goesto trial – howwillyoujustifyyourresults?

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