Fingerprints Lecture 3 Fingerprints How are fingerprints analyzed

Fingerprints How are fingerprints analyzed? Patterns Arch Loop Whorl

Fingerprints How are fingerprints analyzed? Minutiae Bifurcation Dot Ridge Ending Lake/Enclosure

Fingerprint Ridges minutiae- help prove uniqueness of fingerprint Examples: Ending ridge- simple straight ridge

Fingerprints Computer software compares the location of these minutiae.

Fingerprints There are 3 types of fingerprints Visible (patent print) – left by dirt,

Fingerprints There are 3 types of fingerprints Impression (plastic print)– indentation in soft material

Fingerprints There are 3 types of fingerprints 3. Latent – invisible print 3. requires

Fingerprints > Analysis Development and Collection: Scene or Lab? § No rule: Depends on

Fingerprints > Analysis Physical Development: Dusting § Apply powder to latent print or area.

Fingerprints > Analysis Chemical Development: • • • Iodine Fuming Super glue fuming Ninhydrin

Fingerprints > Collection of prints at crime scene: Tape lift: § § Tape placed

Collection of prints from suspect • Ten print card – Roll each print cuticle

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Fingerprints Lecture 3

Fingerprints How are fingerprints analyzed? Patterns Arch Loop Whorl

Fingerprints How are fingerprints analyzed? Minutiae Bifurcation Dot Ridge Ending Lake/Enclosure

Fingerprint Ridges minutiae- help prove uniqueness of fingerprint Examples: Ending ridge- simple straight ridge Bifurcation- ridge that splits into 2 ridges Dot or Island- tiny round ridges Short ridge- small isolated segment of ridge Enclosure (lake)- ridge that forms and forms a complete circle and then becomes a single ridge Trifurcation- ridge that splits into three ridges

Fingerprints Computer software compares the location of these minutiae.

Fingerprints There are 3 types of fingerprints Visible (patent print) – left by dirt, grease, blood, etc. and visible on surface 1. § Does not need processing

Fingerprints There are 3 types of fingerprints Impression (plastic print)– indentation in soft material (butter, putty, tar, etc. ) 2. § Does not need processing

Fingerprints There are 3 types of fingerprints 3. Latent – invisible print 3. requires processing to make visible and suitable for analysis

Fingerprints > Analysis Development and Collection: Scene or Lab? § No rule: Depends on situation § Fingerprint must be photographed after development (scene or lab)

Fingerprints > Analysis Physical Development: Dusting § Apply powder to latent print or area. § Powder adheres to print. Brush and Powder

Fingerprints > Analysis Physical Development: Dusting § Apply powder to latent print or area. § Powder adheres to print. Magnetic Brush and Powder

Fingerprints > Analysis Chemical Development: • • • Iodine Fuming Super glue fuming Ninhydrin Dirty Brown Color

Fingerprints > Collection of prints at crime scene: Tape lift: § § Tape placed over developed print Tape then placed on white card.

Collection of prints from suspect • Ten print card – Roll each print cuticle to cuticle – In order thumb to pinky for each hand