CSI Evidence Collection and Seven S's

Crime Scene Investigation and Evidence Collection Part 2

Multiple Choice

All of the following are ways to improve our observational skills except

• write down and photograph everything you find

• when collecting evidence, record only those things that you are

  sure are important

• observe everything no matter how big or small

• be sure to look at the entire area, not just the body, weapons, or signs of a break-in

Multiple Choice

Is the following an example of Class or individual Evidence: The suspects blood type

• Class

• Individual

Multiple Choice

True or False: A police officer is generally in charge of collecting forensic evidence at a crime scene.

• True

• False

Multiple Choice

Is the following an example of Class or individual Evidence: The suspects footprints

• Class

• Individual

Multiple Choice

Is the following an example of Class or individual Evidence: The suspects fingerprints

• Class

• Individual

Multiple Choice

Locard’s exchange principle implies all of the following except

• Fibers can be transferred from one person to another.

• Blood spatter can be used to identify blood type.

• Cat hair can be transferred to your pants.

• Soil samples can be carried from the yard into your home.

Multiple Choice

Transfer evidence can include all of the following except

• the victim’s own blood gushing from a wound

• hair that was transferred to a hairbrush

• the blood of the victim found on a suspect

• a footprint

Lesson Objectives

• Summarize the seven steps of a crime-scene investigation

• Explain the importance of securing a crime scene

• Identify how a crime scene is documented

• Demonstrate proper technique in Collecting and Packaging trace Evidents

• Describe how evidence from a crime scene is analyzed

Who Investigates a Crime Scene?

• Medical Examiners/Coroners: Maybe present if the crime involves a body

  • Determine a preliminary cause of death

• Detectives: Interview Witness and investigators to put findings together into a preliminary report

• Specialists: Scientific investigators highly qualified in a unique field called in as situations need them

  • entomologists, botanists, psychologists

Forensic Science | Chapter 2: Crime Scene Investigation and Evidence Collection

The Seven S's of Crime Scene Investigation

• There are seven key steps to investigating a crime scene, that must occur in the proper order for an investigation to run smoothly

  • Securing the Scene

  • Separating the Witnesses

  • Scanning the Scene

  • Seeing the Scene

  • Sketching the Scene

  • Searching for Evidence

  • Securing and Collecting Evidence

Forensic Science | Chapter 2

Securing the Scene

• The responsibility of the first responder (Police Officer)

• Number one Priority: Guaranteeing the safety of all individuals in the area

  • Preserving evidence is a secondary goal

• Prevents people from leaving or entering an area

• Collect important information from witnesses and make sure the threat is no longer present

• Calls for specific specialists who may be needed

Forensic Science | Chapter 2

Separating Witnesses

• Making sure witnesses are not talking to each other and comparing what they saw

  • Collusion: cooperation to create a story

    • May or may not be intentional

• As witnesses are separated, the following questions are asked

  • When did the crime occur?

  • Who called in the crime?

  • Who is the Victim?

  • Can you identify the perpetrator?

  • Where were you when the crime happened?

  • What did you see?

Forensic Science | Chapter 2

Scanning the Scene

• Preformed by Forensic examiners

• Quickly look over the scene to determine where photos should be taken

  • Determining the type of Crime scene

    • Primary Crime Scene: The Location a crime took place

    • Secondary Crime Scene: A location related to the crime with evidence, but not the place where the crime took place

      • Example: The home of a suspect

• Assigns priority to investigations

  • Determines what looks to be the most critical to investigate first

Forensic Science | Chapter 2

Multiple Select

Which of the following steps of the investigation can be handled by a first responder? Select all that apply

• Securing the scene

• Separating Witnesses

• Scanning the scene

• There is no problem

Multiple Choice

A store is robbed. One of the witnesses texted her mother, who was shopping on the other side of the store asking if she saw anything. This causes a problem with which step of the investigation?

• Securing the scene

• Separating Witnesses

• Scanning the scene

• There is no problem

Multiple Choice

A store is robbed. The officer who arrives locked down every exit except one that the clerk forgot to tell him about. This causes a problem with which step of the investigation?

• Securing the scene

• Separating Witnesses

• Scanning the scene

• There is no problem

Multiple Choice

A store is robbed. The crime scene investigation crew arrived before the forensic investigator and began searching for evidence. This causes a problem with which step of the investigation?

• Securing the scene

• Separating Witnesses

• Scanning the scene

• There is no problem

Multiple Choice

A store is robbed. The forensic Investigator sees that the perpetrator walked into the main body of the store and committed the robbery there, so they declare that the primary crime scene. This causes a problem with which step of the investigation?

• Securing the scene

• Separating Witnesses

• Scanning the scene

• There is no problem

Seeing the Scene

• Preformed by Crime Scene Investigators

• Involves taking photos of the scene

  • Photos are taken both with and without measurement tools like rulers to help set a scale

  • Certain objects are chosen to help set a baseline for comparison

  • Photos are taken at as many angles and distances as possible

Forensic Science | Chapter 2

Sketching the Scene

• Preformed by Crime Scene Investigators

• A "map" of the scene is drawn on paper to help place all evidence in the location it was found

• Includes all aspects of the scene

  • Furniture, trees, buildings, vehicles

• Shows North and distance scale

• Records date, location, and type of crime

• Is drawn by hand and then generally tidied up on a computer for neatness

Forensic Science | Chapter 2

Searching for Evidence

Forensic Science | Chapter 2

• Preformed by Crime Scene Investigators

• The investigating team chooses a pattern to follow to go over the scene looking for evidence

  • The method used is based on the number of investigators present

    • Single Investigator may use a grid, linear or spiral pattern, while multiple investigators split the scene into quadrants/zones

Searching for Evidence

Forensic Science | Chapter 2

• Use of additional materials may be needed

  • Flashlights: illuminates evidence

  • Forceps: Helps pick up materials without gathering extra material

  • Vacuum with a clean bag: Collects Fiber Evidence

    • Should be used as a last resort, because it picks up extra material

Multiple Choice

A crime scene investigator takes pictures of a piece of evidence but has the ruler upside down so you can't see the scale. This causes a problem with which step of the investigation?

• Seeing the Scene

• Sketching the Scene

• Searching for Evidence

• Scanning the Scene

Multiple Choice

A crime scene investigator needs to scan the area of a crime, but the other people on their team are busy doing other tasks. Since they are working alone, which method of searching would they not use?

• Grid

• Linear

• Quadrient/Zone

• Spiral