Forensic Sciences

Is there a change in state or chemical composition?ex. the car has it's paint chipped.

ex.Most paint chips have 5 layers where this one has 8.

ex.The car must have come from this specific auto shop.

When an object comes in contact with a surface there will always be an exchange of material.

The first general officer on the scene.They will secure the scene to prevent:destruction evidencecontamination of evidenceinterference of the public

pathway where authorized individuals can enter and exit the scene

Sealed area in which evidence may be found

(SOCO)Processes and documents less complex crime scenes.Usually have additional specialized training and photography skills.ex.canine handlingtraffic reconstruction

(FIO)Involved during more severe crimes ex.homicideProcesses the scene more thoroughly.8-10 week intensive training course + additional specialized training

Testing of DNA and bodily fluids

Testing for physical trace evidence and change in physical propertiesex. at a scene of an explosion they can identify if there is any useful evidence

testing of biological and non-biological samples with respect to drugs and alcohol

identifying if a document has been altered or not

Examining potential impressions to identify if a particular firearm or tool was used at the scene of a crime

When an object or material has retained the characteristics of other objects or materials that have been pressed against them.

Usually footwear or tire tracks.

Check all areas within the scene in which we know someone has been.

Light held at a low angle.

To ensure remembering the location and to not disturb the evidence, mark both ends of the impression.

Use Tripod in-order to control shudder speed and depth of field.Position on a levelled surface to not have it tip or fall overInsure the tripod is parallel to the impression to get accurate scaling of the impression.We are photographing in relation to the impression. NOT THE GROUND. Thus if the impression is on a hill and we position it to the ground the image will be distorted.

Only works with a dried wet origin impression.Ex. if you try to use this method with an impression left from a dusty shoes it will not work as the dust will be wiped off.Usually only used on glass and plastic.Fingerprint tape can stabilize an impression onto the surface in-order to move the substrate(ex.glass fragment) instead of trying to remove the impression from a substrate.

Use mylar and apply an electrostatic charge to the foil which takes the dust and cause it to be sucked up and adhered to the mylar.Easy to use and can be reused but very expensive.

Works for both a dried wet origin impression and a dry dust impression.A gelatin layer covered by a clear acetate with a black or white backing. Due to it's extra weight the gelatin sinks onto the floor more than mylar and thus can pick up more of the substrate.Can be used for lifting fingerprints, footwear impressions and even blood impressions.Must be photographed immediately after being lifted due to the layer of clear acetate applied over the impression. This acetate layer prevents you from seeing the impression without peeling the layer back off. Every-time you do so you are risking damaging your impression.(Is a laterally reversed image thus must be corrected)Is a one time use but can be preserved.

Dealing with length width and depth.Thus, you cant just involve photography but also must use a cast.

Just like 2D tripod should be parallel to the impression.

Scale must be level with the bottom of the impression.(Ex Recess the L-scale into dirt instead of leaving it on the surface to get the proper depth perception)Insure that you never place scale or anything over the impression as it obstructs the evidence.

Place light at a 35-45 degree angle.

In certain scenarios ex.snow, the impression may not be visible and thus it is necessary to apply snow-print wax or primer paint in-order to see the impression.Could increase the melting rate of the impression thus needs to be done quickly or under shade.

Allows you to create a replica of the impression or object to bring into court to show the judge and jury.Impression is casted after proper photography is completed and potential debris is removed.A release agent may also be applied to help remove the cast (ex.parting powder)After fully cured the mast needs to be leaned using a course brush.

Only used to cast impressions in snow.After heating up and pouring over an impression one would usually pour dental stone over top for durability due to sulphur being very fragile.

Can be casted on multiple surfaces.After pouring you must wait 30min before removing and another 24 hours before fully cured.

(FW#)There may be multiple foot prints located at the scene thus each must be numbered.

Both the pattern found on human skin(friction ridges) as well as the mark left behind on a surface from making contact with this skin pattern.

The replication of a fingerprint using an ink-pad and paper for later identification.

The natural secretions on the surface of skin mixed with other materials like sweat and foreign materials such a dirt can leave behind an impression/deposit upon contact causing a replication of the fingerprint.

Thick inner layer

Thin outer layer consisting of cells that take a month to shed.Has 5 primary layers:-Stratum corneum-Stratum lucidum-Stratum granulosum-Stratum spinosum-Stratum Basal/basaleThe basal layer is directly in contact with the dermal layer and iis where new cells are formed.

2 layers of skin pegs in-between the dermis and epidermis holding the epidermis in place.