BIOLOGICAL EVIDENCE COLLECTION

By Georgette M, Hannah & Emily (absent)

What is it?

Biological Evidence includes blood of a human or animal, fingernail

scrapings, saliva, urine, hair, fibres from clothing, teeth, bone and skin

tissue. These are collected from a victim and are used for identifying and characterising genetic factors

such as DNA. However, these samples will not count as Biological

Evidence when someone is being tested for drugs, poisoning or

alcohol.

To collect this information, the evidence can be swabbed with wet

cotton wool or even using sticky tape. The evidence will then be

identified (once it is collected) to help with the investigation.

What information can it give a scientist?

Biological Evidence can identify potential suspects and associate

suspects or victims to a crime scene or to one another.

Give an example for one type of insect and how it can identify how long the victim has been dead

Insects can help to identify how long people have been dead, because there are different bugs that show up on a decomposing body in different stages. For example, Necrophagous bugs will show up almost immediately after

death and begin to pick apart the body. These bugs aid in the breaking down and

decomposing of dead bodies. They are drawn to the body by the strong smell of

decomposition.

Bow flies begin to invade bodies within minutes of death, and flesh flies will

follow soon after. Predatory and parasitic insects arrive to feed on

maggot and beetle larvae. As the body dries, hide beetles arrive as well as clothes moths to clean up whatever

remains. An entomologist can identify how long the body has been

decomposing by what types of bugs are present. Also a corpse can be identified by the level of decomposition seen and

the strength of the decomposition smell. These are all tools that aid and

entomologist in Time of Death (T.O.D.).