Forensic science quiz 2

What are the 6 steps of the crime scene process?

preserve, secure, search, record, collect, release

What are the 3 principles of crime scene investigation?

Ensure safety, Prevent contamination, Maintain chain of custody and continuity

What are the different crime scene documentation methods? Why are they important?

note taking, photography, and sketching because if its brough up in court later you have to know what happend

What are the different types of crime scene searches?

Preliminary, Secondary, Final

What are the different types of crime scene search patterns?

Link, line, grid, zone, wheel/ray, spiral

What are scenarios in which certain search patterns are more appropriate for a scene setting than others?

based on the characteristics/location of the scene

What is a chain of custody?

documentation or paper trail showing custody, control, transfer and analysis of everyone who comes in contact with the specimens

Why is a chain of custody important?

Documentation of who controls the evidence from when an item becomes evidence. Helps to show that the evidence being offered has not been tampered with and is authentic.

What components are included on a chain of custody?

Transfer is noted, Any time the evidence is moved, this is recorded, If evidence is destroyed or returned to the owner, this is recorded,

What is Locard's Exchange Principle?

whenever two objects come into contact with one another, a cross-transfer of physical material occurs

What are the necessary components of a rough and final crime scene sketch?

data, markers, and layout elements

What are the differences between a rough and final crime scene sketch?

One is chaotic and full of measurements while the other one is concise and has a legend

How do you scale a final crime scene sketch?

convert the unscaled measurements from your field rough sketch into proportional dimensions using a set ratio, and then draw the layout onto graph paper or computer software with a ruler

What do you measure at a crime scene? What measurements are important?

spatial locations of evidence, structural boundaries, and physical objects

What are rectangular coordinates?

a crime scene mapping technique used to record the exact location of a piece of evidence by measuring its straight-line distance from two mutually perpendicular, fixed reference points—typically the adjacent walls of a room

What is the definition of Bloodstain Pattern Analysis (BPA)

the examination of the shapes, sizes, locations, and distribution patterns of bloodstains, in order to provide an interpretation of the physical event which gives rise to their origin

What are the different categories of bloodstain patterns?

Passive Stains, Transfer Stains, Spatter Impact Stains

What are the different subcategories of bloodstain patterns?

Drops, Drip Stain, Drip Trail, Drip Pattern, Impressions, Swipes, Wipes, Impact, Cast-Off, Arterial or Projection, Forward & Back Spatter, Expirated

What is the difference between a porous and a non-porous target surface?

how the surface interacts with and absorbs liquids like blood

How does the drop height affect the size, shape, and morphology of a bloodstain pattern?

changes the size, edge texture, and satellite formation of the resulting bloodstain

How does the angle of impact affect the size, shape, and morphology of a bloodstain pattern?

directly dictates the geometry, elongation, and peripheral features

How does the target surface affect the size, shape, and morphology of a bloodstain pattern?

directly alter the edge definition, overall size, and secondary spatter

What is a bloodstain tail?

the small, pointed protrusion or extension that shoots off the edge of an elliptical blood droplet when it hits a surface at an angle

How are bloodstains measured?

using geometric and trigonometric principles

How is the angle of impact calculated?

sin-1 (width/length)