Footprints, Tire Impressions, & Bite Marks

patent print

visible when an object picks up soil, dust, paint blood or other material and transfers it elsewhere

latent

hidden from the unaided eye, but can be made visible through dusting

plastic

left in soft materials such as snow, mud, soil, or congealing blood

Ex. of patent

bloody footprint

Ex. of latent

oils, fine soil, & other minute debris being transferred onto clean surfaces polished or newly waxed floors

Ex. of plastic

footprints in mud or snow

What information can be determined from a shoe print?

What were the entrances and exit routes?
How many people were at the crime scene?
Is there evidence of any confrontation or disturbance within the crime scene?
Is there evidence of anyone sustaining injuries?

How are shoe prints class evidence?

size of foot, size of shoe, weight, estimate height

How are shoe prints individual evidence?

the way you wear them
special/specific marks, wearing
step on tack or something it will show up in impression- special qualities

explain how shoes can be individualized by the wearer

shows how you wear them
show how you walk
designed to fit your feet

What information can be taken from footprints left at a crime scene?

estimate of height, weight, foot size, shoe size, brand-wealth, running/walking

explain the procedure for handling an impression at a crime scene

photograph impressions first, lifting latent impressions, electrostatic dusting & lifting, gel lifting, casting plastic impressions

Luminol

makes bloody footprints visible for photography

electrostatic dusting

lifting film charged by electrostatic, holds dust left by a dry shoe; paper or flooring

gel lifting

best used on oily pr moist impressions; thick gel between paper backing and plastic

cast

3D impression

methods for lifting latent prints

dusting
gel lifting
luminol

What are the characteristics that a CSI looks for when tire evidence is present?

1. tire tread patterns and their measurements to identify the type of tire and the possible make and model of car
2. Nature of the impression to determine how the vehicle was driven: tire condition, level of inflation

How are tire tracks class evidence?

it can narrow it down to the type of car or tires

How are tire tracks individual evidence?

Wear marks, nails, patching, and gravel

explain how a CSI can use track width and wheelbase evidence

a large database contains the track width and wheelbase measurements for all the makes and models of cars and can easily checked to identify the vehicles that left the impressions

Ridges

Vertical lines running the length of the natural nail plate, usually related to normal aging.

grooves

indentations; a depression in the tread

ribs

an individual ridge of tread running around the circumference

sipe

small grooves

lugs

fastener, specifically a nut, used to secure a wheel on a vehicle

Rib count

counting the number of ridges. usually about 5

tread

the part of a tire that meets the road; the pattern on the sole of footwear

turning diameter

the diameter of the smallest circle that can be driven by a vehicle

wheelbase

the distance from the center of the front wheel of a vehicle to the center of the rear wheel on the same side

Three different types of skid marks

skid marks
yaw marks
tire scrubs

skid marks

Formed when someone breaks suddenly and locks the wheels, Provides evidence of the distance when breaks were applied, and can help calculate the velocity

Yaw marks

produced when a vehicle travels in a curved path faster than the vehicle can handle and skids sideways
occur when the tire and roads surfaces melt from the extreme temperatures
are always curved

tire scrubs

Produced by a damaged or overloaded tire or tires during or immediately after impact
are usually curved and irregular in width
determine the area of impact

what does turning diameter tell us about a car?

helps determine the size of the vehicle

Is impression evidence alone enough to reach a conviction? Why or Why not

bite mark evidence is not sufficient for a conviction, but does provide circumstantial evidence that may be helpful in building a case

explain the development of teeth from birth to adulthood, including the number of teeth and ages of development

baby teeth come in from the age of one to six. start with 20 teeth
start loosing them at age 6-7
at about 12 or 13 all permanent teeth should be in. 32 teeth

What would a forensic odontologist look for?

DNA to identify a suspect or victim
dental evidence such as bite patterns can help profile suspects in an investigation

explain how the bite marks evidence should be collected

photographed asap. should include ruler
swabbed and tested for DNA