Duties of first responders at crime scenes.
Ensure Personal Safety First
- Assess the scene from a safe distance for threats (e.g., armed individuals, fire, hazardous materials).
- Do not enter until the scene is reasonably safe to approach.
Assist the Injured
- Provide immediate first aid or request emergency medical services (EMS).
- Prioritize saving lives over preserving evidence.
- If a victim must be moved, do so carefully, noting their original position and condition.
Gather Initial Information from Victims
If the victim is conscious and able to speak, quickly collect:
- The assailant’s name (if known).
- A physical description (clothing, height, weapons, etc.).
- Time and method of the attack.
- Any known motive or context.
Record statements accurately and observe the victim’s physical and emotional state.
Conduct a Quick Safety Sweep
Briefly search the area for:
- Suspects still present.
- Immediate threats or hidden dangers (e.g., weapons).
Safety takes precedence, even if minimal evidence is disturbed during this process.
- Prevent Crime Scene Contamination
- Park your vehicle at a safe distance from the scene.
- Avoid walking through or handling potential evidence unnecessarily.
- Use gloves and follow contamination prevention protocols.
Secure the Crime Scene
- Establish clear perimeters using crime scene tape.
- Assign officers to guard entry and exit points.
- Restrict access to authorized personnel only, no bystanders, media, or unauthorized officers
- Observe and Preserve Evidence
- Conduct a visual scan of the scene.
Take mental or written notes on:
- Entry and exit points.
- Visible evidence like weapons, bloodstains, shell casings, etc.
- Any items out of place or suspicious.
Avoid disturbing the evidence.
Identify and Separate Witnesses
Locate and document all potential witnesses.
Collect their names, contact details, and brief statements.
Ensure they do not speak with each other about the incident.
Ask them to remain on scene until investigators arrive.
Detain Any Suspects
If a suspect is present:
- Detain and search them if legally justified.
- Read their Miranda rights if questioning will occur.
- Keep them separate from victims and witnesses.
Protect Fragile Evidence
Use tarps, cones, or vehicles to shield vulnerable evidence from weather or contamination.
Prioritize protection of:
- Bloodstains
- Footprints or tire tracks
- Trace evidence (e.g., fibers, hair)
Document All Actions
Begin written documentation immediately, including:
- Time of arrival and actions taken.
- Observations of the scene and people present.
- Names of EMS personnel, witnesses, officers, etc.
Take photos or sketch the scene if appropriate and before investigators arrive.
Maintain Scene Integrity Until Handover
Secure the scene until detectives or crime scene investigators take over.
Provide a thorough verbal briefing, including:
- Actions taken
- Victim, witness, and suspect details
- Location of all known evidence
Submit a Full Written Report
Your final report should include:
- Detailed observations and decisions made.
- Statements collected from victims and witnesses.
- A list of everyone who entered the scene.
Ensure accuracy and honesty, your report may be used in legal proceedings.
Sketch-mapping methods
Triangulation Method
Definition:
A method where the location of an object is determined by measuring distances from two fixed reference points to the object, forming a triangle.
Advantages:
- High accuracy in irregular or uneven scenes.
- Useful when there are no straight lines or walls.
- Can be applied to indoor or outdoor scenes.
Example Location:
- A forest area where a body is found near natural landmarks like trees or rocks.
- Open field with no buildings or structured boundaries.
Rectangulation Method (Coordinate Method)
Definition:
Objects are located using two perpendicular (right-angle) measurements from fixed reference points, usually along walls or straight edges.
Advantages:
Simple and quick to apply.
Very effective in rectangular or square-shaped rooms.
Measurements are easy to understand and record.
Example Location:
- A bedroom in a house where furniture or weapons need to be measured from walls.
- A bank interior where items like safes, desks, or documents are placed near walls.
Polar Coordinate Method
Definition:
The location of evidence is determined by measuring both the angle and distance from a single fixed point (the origin).
Advantages:
- Effective in large, open areas where evidence is scattered.
- Useful when there’s a central point of interest (e.g., blast center).
- Accurate for uneven terrain or circular layouts.
Example Location:
- A bomb blast site where debris is scattered in all directions.
- A parking lot where vehicles or weapons are located at varying angles from a central point.
Baseline Method
Definition:
Involves establishing a straight line (baseline) between two fixed points and measuring the perpendicular distances from this line to the objects.
Advantages:
Easy to set up and apply in outdoor locations.
- Useful for documenting evidence in a linear arrangement.
- Doesn’t require walls or corners.
Example Location:
- Along a roadside where skid marks, a weapon, and a body are found.
- On a railway track where evidence is found along the line
Evaluation of 5Ws and 1H in Crime Scene Investigation
The 5Ws and 1H are essential components of investigative thinking, helping law enforcement professionals collect complete and actionable information during a criminal investigation. These six questions form the backbone of scene analysis, interviews, and reports.
Who?
Purpose: To identify every individual who may be connected to the incident.
Key Questions:
Who was harmed or affected?
Who is suspected of committing the crime?
Who may have seen or heard the event?
Who first alerted the authorities?
Use in Investigation:
Gathering names through witness interviews or documents.
Linking suspects to the scene using biological or trace evidence such as fingerprints, hair, or DNA.
What?
Purpose:
To define the type and specifics of the criminal act.
Key Questions:
What kind of crime took place?
What item or weapon was used during the crime?
What was taken, damaged, or destroyed?
What pieces of evidence have been recovered?
Use in Investigation:
Classifying the case as murder, burglary, fraud, etc.
Analyzing physical evidence like a weapon, tool marks, or contraband.
When?
Purpose:
To create a detailed timeline of events.
Key Questions:
At what time did the crime occur?
When was it discovered and reported?
When were key individuals last seen?
Use in Investigation:
Establishing the timeframe using surveillance footage, phone activity, or eyewitness accounts.
Estimating time of death or injury through forensic indicators such as livor mortis or environmental factors.
Where?
Purpose:
To determine the exact location and relevant surroundings of the incident.
Key Questions:
Where did the incident take place?
Where was each person involved before and after the crime?
Where was each item of evidence found?
Use in Investigation:
Documenting and photographing the physical environment (room layout, vehicle interior, outdoor space).
Mapping out paths of movement or escape using physical clues or GPS data.
Why?
Purpose:
To uncover possible motivations for the crime.
Key Questions:
What reason might someone have for committing the crime?
Was the act spontaneous or deliberate?
Was there a personal, emotional, or financial motive?
Use in Investigation:
Exploring motives such as greed, revenge, fear, or jealousy.
Examining personal histories, threats, or disputes that could explain intent.
How?
Purpose:
To reconstruct the method and sequence of actions taken during the crime.
Key Questions:
How did the perpetrator carry out the act?
How was access gained to the victim or location?
How did the offender exit the scene?
Use in Investigation:
Rebuilding the incident step by step based on scene evidence.
Determining whether tools were used for forced entry or if access was unforced.
Assessing the physical and forensic evidence to understand the technique or weapon used.
Questions and Answers
Q: What is the first priority of the first officer arriving at a crime scene?
Ans: Ensuring personal and public safety.
Q: What should be done before entering a potentially dangerous crime scene?
Ans: Assess the area for threats like suspects, fire, or hazardous materials.
Q: Why should the patrol car be parked away from the crime scene?
Ans: To avoid contaminating potential evidence and to maintain a tactical advantage.
Q: When can evidence preservation be temporarily compromised?
Ans: When providing urgent medical assistance to victims.
Q: How should officers search for suspects at the scene?
A: Carefully and systematically, with minimal contact with the environment.
Q: What must be done once the scene is secured?
Ans: Cordon off the area and restrict access to authorized personnel only.
Q: What is the officer’s role regarding witnesses at the scene?
Ans: Identify and separate them, but avoid detailed interviews.
Q: Why is it important to separate witnesses?
Ans: To prevent them from influencing each other’s accounts.
Q: What should officers document while at the scene?
Ans: All actions taken, people present, time of arrival, and observations.
Q: When should a formal crime scene handover occur?
Ans: After investigators arrive, and it should be documented clearly.
Q: What is the purpose of crime scene sketching?
Ans: To provide a scaled, accurate visual record of the scene and evidence locations.
Q: Which sketching method involves two fixed points forming a triangle?
Ans: Triangulation method.
Q: Which method uses perpendicular measurements from walls or corners?
Ans: Rectangulation (Coordinate) method.
Q: What method uses angles and distances from a central point?
Ans: Polar coordinate method.
Q: In what type of scene is the baseline method most effective?
Ans: Outdoor, linear scenes like roadsides.
Q: Which sketching method shows walls and ceiling drawn outward to include vertical evidence?
Ans: Exploded view method.
Q: What is a key advantage of the triangulation method?
Ans: It works well in irregular or open areas with no straight boundaries.
Q: Why is the exploded view useful in indoor crimes?
Ans: It shows evidence on all surfaces, including walls and ceilings.
Q: Which method is commonly used in a rectangular room?
Ans: Rectangulation method.
Q: How does the baseline method measure objects?
Ans: Using perpendicular distances from a straight reference line.
Q: What is the main goal of asking “Who?” in an investigation?
Ans: To identify all people involved, including victims, suspects, and witnesses.
Q: What kind of questions fall under “What?” in crime scene evaluation?
Ans: Questions about the type of crime, evidence, and weapons used.
Q: What does “When?” help establish in an investigation?
Ans: The timeline of the incident.
Q: What tools can help answer the “When?” question?
Ans: CCTV timestamps, phone records, and forensic time-of-death indicators.
Q: What does the “Where?” question focus on?
Ans: The crime location and where evidence or people were found.
Q: Why is understanding “Why?” important in criminal cases?
Ans: It helps uncover the motive behind the crime.
Q: Give an example of a motive that could answer the “Why?”
Ans: Revenge, financial gain, jealousy, or self-defense.
Q: What does the “How?” question help investigators determine?
Ans: The method used to commit the crime.
Q: How can investigators answer the “How?” question?
Ans: By reconstructing the sequence of events and analyzing forensic evidence.
Q: Why is using the 5Ws and 1H approach essential in investigation reports?
Ans: It ensures the report is thorough, logical, and legally sound.