Friction Ridge Examination Flashcards
Describe what level I, II and III detail identification is
I - general ridge flow and pattern configuration = isn’t individualised but can exclude an individual
II - formation, bifurcation and combinations = can be individualised
III - all attributes of ridges = can be individualised
What does AFIS stand for?
AUTOMATED FINGERPRINT IDENTIFICATION SYSTEM
Define the three classes of prints
LOOPS - one or more ridges entering, curving and exciting on the same side
1. Ulnar loop - toward fingers 2. Radial loop - toward thumb 3. Contain deltas = point of divergence of two type lines surrounding the loop
ARCHES - plain = gradual rise or tented = sharp peak
WHORLS - plain, central, pocket or double
1. All have 2 or more deltas
Define the terms ‘patent’ and ‘latent’ prints
PATENT - appear because some transferable material on ridge pattern was transferred
LATENT - composed of sweats and oils that persist until fixable by numerous techniques
Define the term ‘friction ridges’
Appear on the palms, soles, finer tips and toes (form around 9-10 weeks of foetal development)
What at the uses and limitations of amido black visualisation methods?
USES
- sensitive to blood
- turns blue black colour in presence
LIMITATIONS
- not stain normal constituents in latent prints
- Not be used as a presumptive test = reacts with more than just blood
What are the uses and limitations for amido black (aq) visualisation methods?
USES
- sensitive to blood
- Blue black colour in presence
- used on nonporous surfaces
LIMITATIONS
- not stain normal constituents in latent prints
- Not used as a presumptive test = reacts with more than blood
- may permanently stain
- corrosive to metal
What are the uses and limitations for leucocrystal violet (aq) visualisation methods?
USES
- develops patent prints stained with blood
- porous or nonporous surfaces
- applied via washing or submersion
LIMITATIONS
- not stain normal constituents of patent prints
- May permanently stain
What are the uses and limitations for gentian crystal violet visualisation methods?
USES
- stains fairy portions of sweat deep purple colour
- works on bloody prints
- visualises latent prints on adhesive surfaces
LIMITATIONS
- may permanently stain
What are the uses and limitations for DFO (1,8-diazafluoren-9-one) visualisation methods?
USES
- reacts with amino acids in body proteins
- Good for paper evidence
- evidence heated once applied
LIMITATIONS
- to recommended for spraying
- special conditions for photography
What are the uses and limitations for glue fuming visualisation methods?
USES
- develops patent prints by binding the proteins in prints
- heated in presence of water to create fumes
- prints dusted to enhance details
LIMITATIONS
- fumes are irritating but non toxic
What are the uses and limitations for iodine visualisation methods?
USES
- develop latent prints on impractical surfaces that can be dusted or has grease residue
LIMITATIONS
- visible for only a few hours
What are the uses and limitations for ninhydrin visualisation methods?
USES
- porous surfaces
- reacting amino abides in latent print residue
- emerged into ninhydrin in fume hood
LIMITATIONS
- avoid contact
- avoid heat or spark exposure
What are the uses and limitations for physical developer visualisation methods?
USES
- silver based liquid reagent
- reacts to lipids, fats, oils and waxes in print residue
- porous surfaces
- last process to use
LIMITATIONS
- numerous safety precautions necessary
- paper with pH above 7 not suitable
What are the uses and limitations for small particle reagent (molybdenum disulphide) visualisation methods?
USES
- small black particles adhere to fairy substances in print residue
- many different surfaces
- wet surfaces or underwater
LIMITATIONS
- numerous safety precautions necessary
- developed prints photographed before lifting attempted
