1. Tools to Solve Crimes
By: Maruful

2. Impressions

3. Key Terms
Impressions: patterns/marks found on surfaces and caused by various objects
Class Characteristics: the general attributes of an object
Individual Characteristics: the specific and unique features of an object

4. Fingerprints Marks left on a surface by a finger tip
Can also be taken of a person’s hand, feet, or toes
Fingerprints are the easiest to work with and classify
They never change and are unique to each individual
Best way to identify an offender (no two people have same finger print pattern)
Even identical twins have different fingerprints

5. Fingerprints (cont.) Two types of prints
Visible fingerprint: can be seen easily, usually because the finger is coated in dirt, blood, etc.
Latent fingerprint: can’t be seen easily, because the finger is coated in sweat and oil. This print needs to be “developed” before its photographed. The methods to develop them are:
Dusting for prints: this is done by using graphite powder which sticks to the print. Then the print is lifted using adhesive tape and placed on a white cardboard surface. This method is used to lift prints off of non-absorbent surfaces ( metal and plastic).
Iodine Fuming: the area being investigated is placed under iodine fumes. This was any fingerprints there will absorb the iodine and become visible. This method is used to lift prints off of absorbent surfaces ( paper and cloth).
Laser Beaming: used to illuminate the print. Prints absorb the laser and turn yellow, and can then be photographed. This method is used to see prints made by sweat compounds

6. Gloves/Shoe Prints/ Tire Tracks
Surprisingly, gloves don’t cover up your tracks as well as you would have hoped
Police can use glove impressions to catch a suspect the same way they use fingerprints
For positive identification they will compare the class characteristics and the individual characteristics with the gloves of a suspect
Shoe prints and tire tracks can also be matched to place the suspect at the scene of the crime
Shoe prints can help determine the suspects height and weight, whether he/she were walk or running, and whether he/she were accompanied
Tire impressions can help investigators figure the type of tires, make of the car, and the direction it was travelling in

7. Key Terms
Fingerprint: a mark left behind after a fingertip touched an object
Visible Fingerprint: the print formed when a fingertip is coated in blood, grease, or some other substance; it is visible to the naked eye
Latent Fingerprint: the print formed by natural oils and perspiration on the fingertip; it is invisible to the naked eye

8. DNA
DNA (Deoxyribonucleic acid) is the building block of an individual’s genetic structure that indicates their physical characteristics such as height, bone structure and eye/hair colour. This molecule is found in every cell in an individual’s body and it is identical to all, however the pattern of the DNA is different for each individual with the exception of identical twins.

9. DNA Testing
DNA testing is a technique used by forensic scientists to indicate an “identification” of an individual from samples such as a few drops of blood or a couple of hair fibres.
A suspect’s DNA identification can be compared with the DNA of the sample from the crime scene which will help determine if the individual is guilty or not. If both profiles correspond with one another, investigators will come to a conclusion that the suspect is in fact the perpetrator of the crime. However, if profiles do not match investigators will have to further their inspection to find another suspect.

10. Procedure for Labelling Evidence
Labelling items of evidence is a very important task that crime officers are responsible for so they can be easily identified at a later date. Accurate labelling also confirms that the evidence has not been contaminated or interfered with in any way. Crime officers are also responsible for establishing a proper chain of custody for the evidence found.
Chain of custody is the witnessed, written record of the people who has control over the items used for evidence. This chain remains unbroken from he time the evidence is discovered at the crime scene to the time it is produced in court.

11. Procedure for Labelling Evidence (cont.)
The chain of custody must show the following:
Who had contact with the evidence;
The date and time the evidence was handled;
The circumstances under which the evidence was handled; and
What changes, if any, were made to the evidence.
All evidence collected at the scene of the crime is tagged and placed in an “evidence package.” The following information typically appears on the package:
Brief description of the item
Police case number
Date when the evidence was collected
Location of collection
Brand name of the item, if any
Serial number or clothing information
Name and badge number of the officer who collected the evidence
Destination of the item for analysis or storage

12. Key Terms
Chain of Custody: the witnessed, written record of people who maintained unbroken control over an item of evidence

13. Cases R. v. Dhillon (2001), B.C.C.A. 555
On April 14, 1977, Carolyn Lee , age 12 disappeared
Around Port Alberni, British Columbia
She was reported missing at around 8:30 by her parents
Her body was found the next day on a farmers property near Cox Lakes
She had

14. Forensic Test Dashed Hopes
Cases
Forensic Test Dashed Hopes
Facts: -Roy Kenshin Lee was going to be declared Canada's victim of a wrongful conviction.
- England's Forensic Science Service used a sophisticated DNA-analysis technique and found that two hairs on the body of the murder victim; Robert Borden, possibly came from Mr.Lee
-Mr.Borden was murdered on April 27, 1987 ( a shadowy figure burst into his bedroom and plunged a sword into his head and midriff)
ISSUES: -The English laboratory determined 1 person in a 100 possess hair matching the DNA profile of the hairs found near the Mr. Borden ( Mr. Lee being among them).
-Controversial witness claimed to have heard Mr.Lee confess murdering 
Decision- Prosecutor Shawn Porter stated that should Mr.Lee take any further action to overturn his conviction, the Crown will be at liberty to use the DNA results against him.
Significance-