Lecture 1 - CSI

Question 1

Crime Scene

Answer 1

where illegal activity has happened and physical evidence can be found (almost anything can be a crime scene - bacterial cell (chemical warfare)

Question 2

Sequence after a scene is recognized as a crime scene

Answer 2

securing the crime scene
recording the crime scene
searching for evidence
recording, preserving, storing evidence

Question 3

Securing Scene

Answer 3

The first person at the scene secures the scene. They are called a “first responder”. This can be police, emergency medical staff, fire department.

FIRST: Ensure safety/state of victim and other first responders (providing medical treatment, transport)
Cordon off area. Secure scene.
Isolate area. Speak to witnesses. Take observations. Note who has access, personnel, etc.

Question 4

Recording crime scene

Answer 4

The crime scene investigator takes over after the scene is secured.
They are responsible for:
recording/documenting the crime scene
identifying and collecting evidence

Question 5

Historically, police and sworn law enforcement have been CSIs.

However, now there is more of a push to have civilians and forensic lab members to be CSIs. Why?

Answer 5

Bias can be present in law enforcement pushing them to prosecution. Corruption leading them to plant evidence, etc.
A civilian tends to have less bias. They can look at it more objectively.

Question 6

However, a CSI is not a lab tech, analyst AND a CSI. One or the other. Being both doesn’t really happen in any jurisdiction. Too heavy of a workload. There is also a fundamental disconnect between CSI and analysts, different duties.

Answer 6

!!!

Question 7

Steps when recording a crime scene:

Answer 7

Document the crime scene, usually by video recording first!
Record entrance/exits, wide angle view, pano view, location, and orientation of evidence, where they are in relation to other objects, the body, etc. Video is critical because crime scenes can change with time rapidly. Can also change because of day/night, weather, environment.
Next is digital photography. Don’t worry about film photography. Take mid-range and close up views of evidence and locations.
Scale bars: show measurements of objects in close up views.
Next, sketching. Sketching captures the spatial relationship between items and evidence. How the room is orientated, where evidence is, etc.

Question 8

3D Scanning

Answer 8

can capture spatial relationships within a scene to sub millimeter resolution. It can’t replace digital photos, but it can replace video and sketching.

Question 9

LIDAR

Answer 9

light detection and ranging - basis for xbox

Question 10

on phones - photogrammetry

Answer 10

stitching together photos for 3d reconstruction. Can capture whole room down to sub millimeter

Question 11

This is becoming more and more common.

Question 12

physical evidence

Answer 12

All objects that can establish that a crime has/has not been committed

Question 13

Issues with evidence collection

Answer 13

Are you collecting/preserving/contaminating everything?
Is the evidence being corrupted?

Question 14

Where can evidence searches happen?

Answer 14

at crime scenes and labs

Question 15

At the crime scene

Answer 15

searches must be unbiased and systematic. Strategies for searching large areas include:
grid or spiral search

Question 16

Why is evidence searched at the lab sometimes?

Answer 16

Objects may be too cumbersome to search on scene.

Ex: Furniture, bed spreads, comforters, cars - this is now the lab tech’s responsibility once brought to the lab, not CSI anymore.

Question 17

N. Italy
Mafia -
Too severely degraded for DNA
Analyzed through the carpet fibers in the rug.
Brought suspect’s car back to lab to check for fibers

Question 18

Identifying physical evidence requires training - Biological stains are hard to see. There are tools to identify certain types of physical evidence, like biological/chemical stains.

Answer 18

ALS

Question 19

Alt. Light Sources

Answer 19

Directs light at different wavelengths towards the surface causing certain compounds to fluoresce.

Question 20

UV light

Answer 20

semen, urine, blood, vaginal secretions, hair, other fibers possible
bacterial cells, spores

Question 21

Blue-Green

Answer 21

bone fragments, teeth, latent prints w or w/o enhancement, some hair and other fibers, bruises, bite marks

Question 22

Infrared (> ~700 nm)

Answer 22

much longer wavelengths, questioned documents, bite marks, bruises (depth dependent)

Question 23

Blue-Green ALS to try to detect bacteria on carpet from illegal biological warfare creation from abandoned buildings when illegal biological warfare was being created.

Question 24

On what evidence to collect/analyze

Answer 24

joint decision that depends on jurisdiction - usually between law enforcement/district attorney, testing laboratory, defense attorney.

Question 25

There can be hard limits on evidence. The lab can say that’s too much evidence - pick two. Then prosecuting attorneys, lead investigator, CSI, and the crime lab director can decide.

However, evidence not chosen can be preserved. It can also be destroyed if a person is found not guilty. Depends on the case, and the verdict. Picking which evidence to keep can be hard!

Sometimes: defense attorneys need to decide which samples to retest.

Because this is based on human judgment, this is tricky. There can also be political pressure to close a case, etc.