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Crime Fighters

In this activity, the class is assigned a crime to solve based loosely on the story of Goldilocks and the Three Bears. Students will experience how forensic techniques are used to collect and process evidence to identify a culprit. With the aid of the Case Bookprovided, students gather and record evidence from tool marks, fingerprints, handwriting, hair samples and shoe impressions to confirm the identity of the culprit. 

Case: Goldilocks and the Three Bears—A tale of Breaking and Entering
After a weekend trip to the city, the Grizzly family arrived late to their cottage home to find it had been vandalized. Upon entering their home, the family found their living quarters in a shambles. Their furniture was upended, food was scattered everywhere, and there was graffiti on the walls. As the family walked through their home, theyfound their son’s chair broken and bowls of porridge left half-eaten in the kitchen. Hearing a noise, Mr and Mrs Grizzly rushed upstairs to catch a glimpse of the vandal as she jumped out of the bedroom window, landing safely in the Grizzlys’ garden before running off into the night. Police arrived shortly after this encounter and proceeded to collect statements, take photos and gather evidence. 

Police searched the surrounding area and compiled a list of suspects matching the description given by the Grizzly family.

Activity Stations:

1 - Tool Mark Analysis
2 - 
Fingerprint Identification
3
 - Handwriting Analysis 
4 - 
Hair Sample Analysis
5- 
Shoeprint Identification

Objectives

  • Carefully compare, analyze and record various types evidence (shoe prints, tool marks, handwriting, fingerprints, and hair/fibre) to infer a likely suspect.

Materials

  • Per student:
    1 Crime Fighter’s Case Book
    pencil

    Per station:
    evidence to be examined (See each activity link for details for each station)

Key Questions

  • What kind of evidence did you need to solve the crime? Where did all of the evidence come from? How was it collected? How were suspects identified? How challenging was it to solve the crime? At which point did you become certain that you knew the identity of the culprit? Why? How confident are you that you identified the real culprit? Which types of evidence did you think were most convincing? Do you think you might have made any errors in examining the evidence? When and why? How was this similar to what real forensic scientists do? How was it different?

What To Do

Preparation

  1. Identify three suspects who are able to keep their identity a secret throughout the activity. Designate one of these suspects as the culprit. You may choose student or other adults and/or teachers familiar to the students. 
  2. Collect the evidence you require from the three suspects (including fingerprints, hair samples, etc.) Use the templates provided for each station. For the stations where all of the evidence is provided, Suspect B is the culprit, so any evidence you gather yourself should also identify Suspect B as the culprit. 
  3. Gather the equipment required and set up the investigation labs (stations), where students will act as detectives to solve the crime. Create a station for each type of evidence.

Activity

  1. Introduce the class to the crime, and hire them to be the detectives who will identify the culprit. 
  2. Introduce the stations and the type of evidence students will be collecting at each one, and explain how to collect evidence.
  3. Split the class into groups, hand out copies of the Crime Fighter’s Case Books to each student, and rotate the groups through each station. The crime is solved when the students have completed all stations and have discussed the results with the teacher and the rest of the class.

Extensions

  • Try another mystery using the same format and types of evidence, but have each group work separately and report to a head detective. Identify the culprit by sharing the information that each group reports. (This is how real forensic scientists work, with each specialist reporting their findings.) How does this change the investigation?

Other Resources

Science World Resources | Full Lesson & other activities | Science Detectives