Forensic SAC 1

What is a ballistics expert?

Ballistic experts are forensic scientists that are interested in the functioning of firearms and their ammunition.

What is an odontologist?

A dentist who specialises in teeth and bite mark evidence.

What is a toxicologist?

A specialised field in chemistry where professionals study the substances are are harmful or poisonous to the human body.

What are entomologists?

Forensic experts that look at arthropods and insects.

Evidence is...

anything that can be used in court to support a case.

What is step 1 of crime scene processing?

Secure the scene

What is step 2 of crime scene processing?

Examine the scene

What is step 3 of crime scene processing?

Photograph the scene

What is step 4 of crime scene processing?

Sketch the site

What is step 5 of crime scene processing?

Process the scene

What are 2 reasons why a witness's memory might be affected?

1. Focus on the perpetrators face for a minute or longer rather than 30 seconds will tend to have a more accurate memory

2. Faces that are either highly attractive or highly unattractive are more likely to be accurately remembered.

What is a leading question

When misinformation is planted into the witness's memory using descriptive words that indicate greater severity.

What is physical evidence?

Any large material items found at the crime scene, on the victim/s, or found at the suspects possession.

What is trace evidence?

Physical evidence that is found in small but measurable amounts.

What is the difference between physical evidence and trace evidence?

Physical evidence is any large material items whereas, trace evidence is found in small but measurable amounts.

What is the chain of custody?

Each move of the item is logged, signed and dated.

Hair does not easily_________

decompose

Chemical tests on hair can provide information about...

the use of drugs, other toxications and the prescence of nutritional deficiencies.

When can hair be used as DNA?

When the foliclle is present

Hair is composed of______

the protein keratin which makes the hair strong and flexible.

What is the cuticle?

Outer layer of hair and is composed of overlapping scales.

What is the cortex?

protein rich structure around the medulla that contains pigment

what is the medulla?

the central core that might be absent. May very in opacity and continuity and helps differentiate between difference species but not different people.

What part of hair structure is the most important when differentiating between different people?

cortex

What is a fibre?

The smallest unit of a textile material.

What are natural fibres?

Fibres that come from plant or animals and are used for the production of fabric. Not man-made.

What are synthetic fibres?

Fibres that are man-made.

How can we use fibre as evidence?

Matching unique fibres of clothing on a victim to the fibres of a suspect's clothing can be very useful.

What are fingerprints

the marks left behind when someone touches an object with their fingers.

How are fingerprints made?

When you touch and object, a small amount of secretions are left behind on the object that mimic the ridges on your finger.

What are the 3 way to make fingerprints?

1) impression

2) mark

3) invisible

How is an impression print made?

left in something soft. example - wet paint/soap

How is a mark print made?

Left on something by transfer. - example blood/dirt

How are invisible prints made?

Small amounts of oil and perspiration are secreted from microscopic pores in the ridges of the fingertips.

Invisible prints need to be_________

developed

What is a delta?

A triangular shape formed where 2 patterns meet in a fingerprint.

What is the core?

The core of the print is found in the centre of the pattern

What are the 3 fingerprint types?

- arch

- loop

- whorl

The arch______

runs from 1 side of the finger to the other making a backwards turn. has no delta.

The loop_______

makes a backwards turn and comes out the same side. has one delta

the whorl_____

where ridges form a complete turn. has 2 deltas

the radial loop has ridges that slope __________ _____ ________

towards the thumb

the ulnar loop has ridges that slope __________ _____ ________

towards the pinky

How are fingerprints used in forensic investiagtions?

Fingerprints of all people at a scene are taken and compared to the ones found at the scene. Forensics can then eliminate those people that are not a match.

Dusting is used on _________

hard, non-porous surfaces like glass

Name the 2 dusting powers used.

1) talcum powder

2) carbon powder

when dusting, the powder sticks to the_______

moist parts of the impression.

What is used to lift prints?

sticky tape

When is superglue used?

on smooth, non-porous surfaces like metals and leather.

The glue leaves a _______

clear white deposit

what does superglue react with?

the amino acids, fatty acids and proteins

When is ninhydrin used?

on porous surfaces such as paper or glue.

What does ninhydrin react with?

the amino acids

What colour does ninhydrin show up as

purple/pink

when is iodine fuming used?

on porous surfaces such as cloth

the iodine fumes react with _______

the oils

when is menthyl violet used?

if fingerprints have been left on sticky surfaces

what does the menthyl violet absorb

fatty acids

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