Jon Benet Ramsey Case: House not searched for 7 hours because

assumption was that it was a kidnapping Only the girl’s bedroom was sealed initially Father found the body in the basement,

wrapped her in a blanket and carried her upstairs

After body was found, people allowed to move about freely in house

House was cleaned

Locard’s Exchange Principle – A) when a person comes into contact with an object or another person, a cross-transfer of physical evidence can occur.

B) the intensity, duration and nature of the materials in contact determine the extent of the transfer.

Animal or human hair Fingerprints Soil or plant material (pollen) Body fluids like mucus, semen, saliva,

blood Broken glass/paint chips/chemicals Fiber from clothing

Police officers – usually first to arrive CSI’s – document crime scene in

detail/collect physical evidence…include recorders for the data, sketch artists, photographers, evidence collectors

Medical Examiner – (coroner) to determine cause of death

Detectives – interview witnesses, talk to CSI’s about evidence

Specialists – entomologists, scientists, psychologists

Direct: Firsthand observations (eyewitness accounts,

police dashboard cameras); confessions

Circumstantial: Indirect evidence that can imply a fact but

doesn’t directly prove it Can be either physical or biological Trace evidence is an example

Physical: Impressions from fingerprints, footprints, shoe prints, tire impressions, tool marks, fibers, weapons, bullets, and shell casings

Biological: body fluids, hair, plant parts and natural fibers

Class evidence: narrows identity to a group of people (blood group for example)

Individual evidence: narrows identity to a single person/thing

1. Securing the Scene Responsibility of the first responder Safety of everyone in vicinity is top priority Evidence preservation is second priority

2. Separating the Witnesses Avoids collusion Questions that should be asked include:

A) When did the crime occur? B) Who called in the crime? C) Who is the victim? D) Can the perpetrator be identified? E) What did you see happen? F) Where were you when you observed

the crime scene?

3. Scanning the Scene Primary crime scene Secondary crime scene

4. Seeing the Scene CSI’s need to see the scene Photos with and w/out rulers should be taken Triangulation of stationary objects should be

included for reference points

5. Sketching the Scene Position of body (if any) and any other

evidence Should be measured from 2 immovable

landmarks North should be labeled and a scale should be

provided Positions of furniture, doors (inside), shrubs,

trees (outside) should be included

6. Searching the scene Common search patterns include the spiral, strip/line, grid,

zone/quadrant, and pie/ wheel.

The spiral search is used most often for outdoor crime scenes, is conducted by one person, and is done by walking in a circle from the outermost point of the inner perimeter toward the center of the circle.

The Linear search is done by dividing the crime scene into a series of lanes in which personnel search up and down the lanes until the scene is completely searched. A grid search is similar to a line search but is also divided into lanes perpendicularly, thereby constituting a more systematically thorough search from multiple perspectives.

A Quadrant search is one in which the crime scene is divided into four quadrants and searched using another method, such as a strip or line search.

In a Wheel/Pie search, the crime scene is divided into a large circle with numerous sectors, and searched using another method, such as a strip/line search.

Practically speaking, line or grid search is used most often (Swanson, Chamelin, and Territo 2003).

7. Securing and Collecting Evidence Proper packaging, sealing and labeling is vital

Liquid/arson remains in airtight/unbreakable containers

Biological evidence in breathable containers so it can dry out

Must include a evidence log and chain of custody

Evidence log: case number Item inventory number Description of evidence Name of suspect Name of victim Date/time of recovery Signature of person recovering the evidence Signature of any witnesses present during

collection

Chain of custody: Indicates every person who has handled the

evidence Log must be attached to packaging

After evidence has dried, it is packed in a paper bindle (aka druggist’s fold)

Then it can be put into a plastic or paper container, labeled with evidence tag, sealed and taped with the collector’s signature across the taped edge.

Control samples must also be obtained from the victim for exclusion purposes.

Essential to maintain

Original collector: bags evidence properly, labels it properly, seals it and signs the sealed edge.

Next person to receive evidence signs that they received it (lab technician for example); lab tech opens sealed container at a location other than the sealed edge; after examination, tech repackages , signs log and reseals with new tape/signature.

Importance of Chain of Custody

Done in forensic labs – the largest is the FBI crime lab

Forensic lab technicians are specialists – unlike what you see on tv

Results sent to lead detective who then attempts to reconstruct the crime scene

Involves forming a hypothesis about what happened before/during/after the crime

Witness accounts and forensic evidence are used to form the hypothesis

So what happens if the evidence doesn’t match the witness statements?

1. Arson – fire set to cover up another crime

2. Suicide/murder – victim murdered/stage set to appear as a suicide

3. Burglary – staged to collect insurance money

Initially treat all death investigations as homicides

Do the wounds match the weapon used? Could the wounds be easily self-inflicted? Profile the victim via interviews with

family/friends Corroborate statements with evidential

facts. Reconstruct the event – does it make

sense?

http://www.practicalhomicide.com/Research/staging.htm