CASE OF THE GOURMET DELIGHT

 

      Everyone knew that Mrs. Weitzel had food allergies. Only a few teachers knew what the food allergy was because she is very private about the matter. Somehow the very substance that Mrs. Weitzel cannot eat was served at the buffet in the teachers’ center. Mrs. Sopko was sitting next to Mrs. Weitzel when she collapsed into Mrs. Sopko’s arms.  Mrs. Sopko said Mrs. Weitzel had just taken a bite of food and a sip from her drinking cup. Mr. Wilson called 911.

       As the paramedics attended to Mrs. Weitzel, they noticed a white powder around her   mouth and a yellow powder floating on top of her drink cup. Using a paper towel, a paramedic carefully wiped the residue from her upper lip and placed the cloth next to the gurney.  As the paramedics moved Mrs. Weitzel to the ambulance, the cloth with the white powder was bagged as evidence. The cup was also taken to forensics’ evidence room.

On the table where Mrs. Weitzel had filled her plate were six different dishes of food.  Four of them held recipes with a white powder sprinkled on top.  The other two containers used a dry white powder in the recipe.

     Looking more closely at the serving dishes, both partial and full fingerprints were evident. 

     There were other pieces of evidence at this crime scene.

1.     There was a note on the table. 

2.     A strand of hair was lying on top of one of the prepared delicacies.

3.      Further, someone must have gotten a bad snag in his or her clothing because threads were attached to a nail that was protruding from the lower left side of the tabletop.

4.     Several students heard the sound of tires screeching. One student said it was either a white or silver car or not, and they said it looked like one of those old 2001 Nissan Pathfinder’s.

      Read about each substance. Determine which substance could cause an allergic reaction or poisoning, and determine who could have poisoned Mrs. Weitzel.  This crime needs to be solved!

 

 

 

 

 

CAN YOU SOLVE THIS CRIME?

 

What questions need to be investigated? _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________

 

 

Clues have been provided.  List them below:

 

 

 

 

 

 

 

DATA TABLE 1

Observations from tests on white powders.

*If you don’t know what these items are, look for clues in your lab kit-the answers are there.

Name of

known substance

Observation

with hand lens

Addition of

acetic acid  *

Addition of

water

 

Addition of

Sodium

Carbonate *

A –

 

 

 

 

 

 

 

 

B –

 

 

 

 

 

 

 

 

C –

 

 

 

 

 

 

 

 

D –

 

 

 

 

 

 

 

 

E –

 

 

 

 

 

 

 

 

F –

 

 

 

 

 

 

 

 

 

1.     Compare your observations to the Control’s observations. Match the substances and record their names.

2.     Investigate the chemical composition of these substances.

 

 

Now research 3 of the white substances you found that might be poisonous or trigger an allergic reaction.

 

Double check the recipes for the dishes made to see if any of these ingredients were used in the dishes.  Perhaps the culprit used more of the ingredient than necessary for the recipe.

 

 

 

 

Since 1901, fingerprinting has been used as a method of positively identifying individuals. Because no two people have the same fingerprints, a good print can help solve a crime.(Crime Scene Investigations)

 

Read about fingerprinting:  http://www.bergen.org/EST/Year5/fingerprint.htm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 2

 

Observations from fingerprint samples.

 

Finger Samples

 

 

 

 

 

 Number 1

 

Number 2

 

Number 3

Number 4

Matches

 

 

 

 

 

 

 

 

 

 

Match the samples to the Control’s samples. Record the name for each number sample.

Collect samples from the dishes. Compare dish samples to Table 2 samples and determine the name matching the prints.

 

 

 

 

 

The Police searched the homes of the suspects and seized articles of clothing for potential matches to the threads found at the scene of the crime. Investigate the characteristics of these fibers. Do your research before conducting your experiments.

 

 

TABLE 3

Read about fibers as evidence: http://www.uclan.ac.uk/facs/science/forensic/whatis/Fibre_files/frame.htm

Fiber Identification:  http://www.fabrics.net/fabricsr.asp

 

Observations from fibers.

 

 

 

 

Staining

Cleaning stain

Odor

Residue

Fiber found at the scene

 

 

 

 

 

 

Wool

 

 

 

 

 

 

 

 

Rayon

 

 

 

 

 

 

 

 

Silk

 

 

 

 

 

 

 

 

Polyester

 

 

 

 

 

 

 

 

Cotton

 

 

 

 

 

 

 

 

 

 

Match your observations to the material in the Control envelope to determine which cloth was snagged on the nail.

 

 

An observer who saw the vehicle as it peeled away noticed that the vehicle ran over some Xerox paper that had probably blown out of the recycling dumpster and landed in the path of the get-away vehicle. The observer did not have time to get the license plate number or model of the vehicle, but knew it was white, and there were tread marks left behind on the Xerox paper lying in the road.

 

Begin your investigation for the tire treads by going out to the staff parking lot. Compare the tire treads on the white vehicles to that of the evidence left on the Xerox paper.

1.     Examine the tires of the white vehicles

*  When looking at the number of treads count the number of vertical rows

*  When looking at the number of grooves, count the number of the vertical spaces between the treads on the tire.

*  When looking at the size of the grooves/treads, look to see if they are large, medium or small.

*  If they are large, that means they are pretty wide.

*  If they are small, that means they are fairly skinny.

*  If they are medium, that means they are a little in between large and small.

2.     Fill out the worksheet below for the white vehicles in the parking lot.

3.     Based on your answers below, which car tire matches the imprint left by the suspect? Explain your answer.

 

 

Suspects

License Plate #

Tread Size

(large, med, small)

Tread Number

Groove Size

(large, med, small)

Groove number

Worn/Unique Spots

Photo of tire track found when suspect left

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hair Analysis:

 

Read about hair found at the scene of a crime and what it can tell you:  http://www.uclan.ac.uk/facs/science/forensic/whatis/Hairs_files/frame.htm

 

http://www.crimelibrary.com/criminal_mind/forensics/trace/5.html

 

http://www.crimeandclues.com/hair_evidence.htm (Structure of hair)

 

Observe the hair taken from the food.

 

Now observe the hair collected from the suspects.

Characteristics

Sample taken from crime scene

 

 

 

 

Color

 

 

 

 

 

 

Length

 

 

 

 

 

 

Other features

(read structure of hair at site above)

 

 

 

 

 

 

 

What yellow substances float on top of water? Construct a table labeling each substance and write your observations in the table next to the labeled mixture.

 

 

What types of forensic evidence were discovered at the scene? ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

 

What method of chemistry was used to tie the evidence to the crime? _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

 

What evidence will be used to convict the suspect? Why? ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________