The Crime Scene

How Are Your Observation Skills?This activity demonstrates our ability to remember details

accurately. Testimony about personal experience is frequently used

during an investigation. How accurately do people remember what they have

seen? What factors may play a role in what we can remember

and describe about something we have witnessed? Consider these questions as you do the following activity.

Directions:1. Observe the picture for exactly 30 seconds.

Look at everything you think might be important.

2. After 30 seconds, answer the questions3. How observant were you? Compare your

answers to the picture.

READY

Questions1. What time was it on the clock?

2. How many people were in the scene? How many males? females?

3. Describe the person at the front of the line. Was it a man or a woman? Was he or she wearing a hat? What kind of clothes was the person wearing? Could you tell how tall the person was? Did he or she have any distinguishing features?

4. What day of the month was it?

5. Did you notice anything unusual in the picture?

Did you know?Eyewitness misidentification is the single greatest cause

of wrongful convictions nationwide, playing a role in more than 75% of conviction overturned through DNA testing

Still, the criminal justice system relies on eyewitness identification and testimony for investigating and prosecuting crimes

Crime Scene VocabularyCrime Scene: Any physical

location in which a crime has occurred or is suspected of having occurred

Primary Crime Scene: The original location of a crime or accident

Vocabulary cont….Suspect: Person thought to be

capable of committing a crime

Accomplice: Person associated with someone suspected of committing a crime

Alibi: Statement of where a suspect was at the time of a crime

Physical Evidence: Encompasses any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or crime and its perpetrator

Approaching a crime sceneFirst priority should be

given to obtaining medical assistance for individuals in need of it and to arresting the perpetrator

Personal safety and the well being of victims

Preserve and isolate the crime scene

Record the crime scene

Crime scene personnelPolice officersTypically the first to arrive at

a crime sceneThey are responsible for

securing the scene so no evidence is destroyed and detaining persons of interest in the crime

Personnel cont….CSI unitDocuments the crime scene

in detail and collects any physical evidence

Personnel cont….District attorneyOften present to help

determine if any search warrants are required to proceed and obtains those warrants from a judge

Personnel cont….Medical examiner (if a homicide) may or may

not be present to determine a preliminary cause of death

Personnel cont….Detectives Interview witnesses and

consult with the CSI unit Investigate the crime by

following leads provided by the witnesses and physical evidence

Crime Scene ProtocolStep 1: InterviewThe first step in investigating a crime scene is to interview the first officer at the scene or the victim to determine what allegedly happened, what crime took place, and how was the crime committed. This information may not be factual information but it will give the investigators a place to start.

Step 2: ExamineThe second step in the investigation of a crime scene, which will help identify possible evidence, identify the point of entry and point of exit, and outline the general layout of the crime scene.

Step 3: DocumentThe third step in the protocol involves creating a pictorial record of the scene as well as a rough sketch to demonstrate the layout of the crime scene and to identify the exact position of the deceased victim or other evidence within the crime scene.

Step 4: ProcessThe crime scene technician will process the crime scene for evidence, both physical and testimonial evidence. It is the crime scene technicians responsibility to identify, evaluate and collect physical evidence from the crime scene for further analysis by a crime laboratory.

Recording the crime scene….Photographs

Scene Evidence

Multiple views

Entrances

Exits

Windows

Close ups

Perspectives

Multiple angles

Recording the crime scene….SketchA draft representation of all

essential information and measurements at a crime scene

It shows all recovered items of physical evidence, as well as other important features of the crime scene

Recording the crime scene….NotesRecord of actual

measurements of the scene, evidence and the relationship between them

Match to sketchUse a key

Collecting EvidenceBag and Tag

Victims clothingFingernail scrapingsHead and pubic hairsBloodHydrocarbons (arson)Recovered bullets from

the body and/or surrounding area

Hand swabs or washings from shooting victims

Documentation…Chain of custodyDescription of itemLocation in crime scene from

which collectedCase numberDate/time collectedSignature of collector

They must identify The time an item was

discovered By whom How and whom it was

packaged and marked

Rules for evidence collectionMaintain the physical

integrity of a sampleLimit degradation (the act of

degrading)Prevent contaminationChain of custody

The Seven S’s of Crime Scene Investigation

1. Secure the scene2. Separate the witnesses3. Scan the scene4. Seeing the scene5. Sketch the scene 6. Search for evidence7. Secure the collected evidence

Forensic science servicesForensic pathology Involves the investigation of

unnatural, unexplained or violent deaths

Charged with determining the cause of death

May conduct autopsy which is a medical dissection and examination of a body in order to determine the cause of death

Forensic science services…contForensic anthropologyConcerned with the

identification and examination of human skeletal remains

Forensic science services…contForensic entomologyThe study of insects and

their relation to a criminal investigation, commonly used to estimate time of death

Stages of deathRigor mortis Results in the shortening of muscle tissue and the stiffening of

body parts in the position at death (occurs in the first 24 hours and disappears within 36 hours)

Livor mortis Results in the settling of blood in areas of the body closest to the

ground (begins immediately on death and continues up to 12 hours)

Algor mortis Results in the loss of heat by the body (general rule..the body loses

heat by 1 to 1 ½ degrees Fahrenheit per hour until the body reaches the environmental temperature)