The Crime Scene

Coach Whitaker

Vocabulary Crime Scene—any place where evidence

may be located to help explain events Modus Operandi—the characteristic

method of operation of a criminal Chain of Custody—a written record of all

people who have had possession of an item of evidence

Alibi—statement of where a suspect was at the time of a crime.

Vocabulary Accomplice—person associated with

someone suspected of committing a crime Suspect—person thought to be capable of

committing a crime Secondary Crime Scene—an alternate

location where additional evidence may be found

Primary Crime Scene—the original location of a crime or accident

Crime Scene

What evidence can be found at a crime scene? Brainstorm with your group to come up with a list of evidence you might find at a crime scene.

What is the difference in a primary and secondary crime scene?

Name some potential primary and secondary crime scenes in the following scenes-------bank robbery, burglary, murder, theft, assaults.

At the Crime Scene Forensic Science Begins at

the Crime Scene which can provide useful information that must be carefully, systemically, scientifically, and legally collected

The information and evidence at the scene that must be used later to reconstruct the scene and events that led up to the crime

It establishes the MO and the motive for the crime

At the Crime Scene The main reason to carefully analyze the

crime scene is to learn what happened and to gather evidence to convict the suspect

The CSI’s experience, knowledge, and capabilities are critical for deciding which items at a scene are actual evidence

If errors at made at the scene in protecting, processing, and analyzing the evidence it can be thrown out in court

Steps in Handling the Crime Scene

1. Preserving and Isolating the Crime Scene

2. Observing and Documenting the scene

3. Searching the scene for evidence

4. Collecting and packaging evidence

5. Maintaining Chain of Custody

Crime Scene Personnel POLICE OFFICERS are typically the first to arrive at a crime

scene. They are responsible for securing the scene so no evidence is destroyed and detaining persons of interest in the crime.

The CSI UNIT documents the crime scene in detail and collects any physical evidence.

The District Attorney is often present to help determine if any search warrants are required to proceed and obtains those warrants from a judge.

The MEDICAL EXAMINER (if a homicide) may or may not be present to determine a preliminary cause of death.

SPECIALISTS (entomologists, forensic scientists, forensic psychologists) may be called in if the evidence requires expert analysis.

DETECTIVES interview witnesses and consult with the CSI unit. They investigate the crime by following leads provided by witnesses and physical evidence.

Preserving and Isolating the Crime Scene

The first officer on scene determines the nature of the crime and has the following responsibilities:

1. Get medical assistance if needed (saving lives is the first priority even if it means disturbing the crime scene)

2. Make an arrest3. The scene must be secured

and protected against any unauthorized person from entering it

4. Suspects and witnesses must be detained

5. Protect and preserve evidence at the scene

Preserving and Isolating the Crime Scene

The investigator interviews the first responder, victim, or witnesses to learn what may have happened

Police officers note and record details such as weather conditions, odors, lights, signs or prior activities at the scene, etc

Activity Forensic Science on the Net Name

___________________________ CHIN – Interactive Investigator http://www.virtualmuseum.ca/Exhibitions/

Myst/en/game/index.phtml

PDF Worksheet http://sciencespot.net/Pages/classforsci.html

Observing and Documenting the Scene

The investigator should do the following:

1. Examine the scene to get an overall view to find pieces of evidence

2. To ID the points of entry and exit

3. To consider what may have happened

4. To mentally outline how the scene should be handled

KEEN OBSERVATION ANDDETAILED NOTES ARECRITICAL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Observing and Documenting the Scene

Notes—the most important parts of processing the scene. Why?

1. Forces investigators to more observant (makes you focus on details you would miss or overlook)

Notes should be complete and written clearly and legibly

They should detail step by step every action that the investigator takes in the order it happened

Observing and Documenting the Scene

Notes should include:1. Date and time2. Location, environment,

weather description3. Description of the scene4. Written description of

physical evidence, location, time of discovery, and packaging

5. Names of the people involved

Observing and Documenting the Scene Photographs“A picture is worth a thousand words”Before making any detailed examination ortouching the scene, an investigator mustphotograph the scene Pictures help CSI remember details, show

where evidence was placed in the scene, and help jury and judge visualize the scene

Observing and Documenting the Scene

The investigator must include photos that:

1. Clarify the scene2. Close up of evidence3. Views of the witness4. Location and

surroundings of the crime

5. Objects from different angles

6. Rule to scale7. Are documented for

evidence

Observing and Documenting the Scene

Videotaping The investigator can

narrate relevant information while moving through the scene

Observing and Documenting the Scene Sketches Sketches give photographs perspective Gives a permanent record of the

relationships of different points of interest to each other in the scene

Gives a better layout The sketch must have measurements,

scale, and correct placement of details Combines note with photos

Activity Sketches, Photos, and videotaping http://sciencespot.net/Pages/

classforsci.html

Investigation Discovery (PDF) AT  

Searching the Scene for Evidence

Without evidence even the most heinous crimes will go unpunished

The care that is taken collected evidence directly impacts the police ability to prosecute crimes

Evidence can be damaged, contaminated, or even lost which makes it useless to the crime lab and inadmissible in court

Searching the Scene for Evidence The first step is finding it by taking an

orderly approach to search the scene Many items will be visible while others are

not The way investigators search the scene

depends on the size and physical layout of the area in question

Searching the Scene for Evidence Searchers usually following a

geometric pattern, some examples include:

Grid Search

Searching the Scene for Evidence Linear Search

Searching the Scene for Evidence Quadrant or Zone

Searching the Scene for Evidence Spiral Search

Search Activity Search Using different stories, crimes, and

scenes (Courtyard)

Gathering the Evidence The next step is collect and

package the evidence The investigator must put

each item in a separate container and label it

When collecting evidence, investigators start with evidence that is fragile or that is likely to be lost, damaged, or contaminated, such as blood, fibers, hair, fingerprints, shoeprints, and tire tracks

Gathering the Evidence Generally, pill bottles, vials, manila

envelopes, and plastic bags are good container for most evidence

Special considerations include: Wet items must be dried before packaging Containers must be sealed to prevent

leaks or breakage Biological items should be dried and kept

in a freezer

Gathering the Evidence Clothing with trace

evidence should be packaged carefully to avoid disturbance

Firearms should be fixed rigidly inside a wooden container

A collection may be made using adhesive tape

Gathering the Evidence Gathering delicate evidence Fingerprints are photographed and then lifted or

transferred to a material Tool marks and shoeprints or tire impressions are

photographed before being lifted or casted Fibers and hair are searched for with alternative

light sources and picked up with tweezers Carpets and furniture are vacuumed with a clean

bag for each area

Control Samples Control Samples are

samples with a know origin. For example, blood from a scene compared to the blood of the victim

These control samples must be collected and compared with samples from the scene

All evidence should be sealed with tamper proof tape and properly labeled

Gathering Evidence Activity Search Using different stories, crimes, and

scenes (Courtyard) Collect Evidence and Package List for each crime

Chain of Custody There must be a

written record of who has had possession of the evidence at all times

The court needs to know who has been responsible for evidence from the time it was collected to time it appears in court

Chain of Custody The record will show: Who collected the evidence Who had contact with the evidence At what time Under what circumstances And if changes where made to the

evidence

Chain of Custody The record is usually

on the package itself It is not uncommon for

everyone who came into contact with the evidence to testify in court

Chain of Custody After the scene has

been processed and investigated, evidence is sent to the forensic lab or stored

Unit Project Crime Scene Processing Project Elements (three scenes) (2 Groups) Secure scene Invent own crime Notes, photographs or videos, sketches,

search, evidence gathering and packaging, and Chain of Custody

Photostory or Movie maker about crime

Checklist for finding five pieces of evidence, chain of custody, Crime scene log,

Draw a detailed sketch with notes