Crime Scene Safety
The first priority when arriving at any crime scene.
What is ensuring the safety of victims, responders, and bystanders?
This physical boundary keeps unauthorized people away from the crime scene.
What is the crime scene perimeter?
After addressing immediate safety and medical needs, the first responder should do this to the scene.
What is secure and isolate the scene?
Crime scene notes should be written at this time rather than relying on memory later.
What is during the investigation/as observations are made?
These photographs show the entire scene and establish its overall layout.
What are overall photographs?
Gloves, eye protection, masks, and protective clothing are examples of this.
What is personal protective equipment (PPE)?
This record documents everyone who enters and leaves the scene.
What is the scene entry/exit log (scene access log)?
Potential witnesses should usually be kept apart for this reason.
What is to prevent them from influencing or changing each other's accounts?
Notes should include facts and observations, but avoid unsupported versions of this.
What are opinions, assumptions, or conclusions?
These photographs connect a specific item of evidence to its location in the scene.
What are midrange photographs?
Blood, bodily fluids, needles, chemicals, weapons, fire, and unstable structures are all examples of these.
What are potential scene hazards?
Moving, touching, or altering evidence unnecessarily can damage this.
What is scene integrity?
A first responder should record the names of people present and also note this important timing information.
What are arrival, entry, exit, and/or key event times?
Date, time, location, weather/lighting, names of personnel, observations, and actions taken are examples of what belongs in these.
What are crime scene notes?
These photographs capture fine detail of a specific item of evidence.
What are close-up photographs?
A responder should change gloves between handling different pieces of evidence mainly to prevent this.
What is cross-contamination?
This principle explains why every person entering a scene can bring something in or take something away.
What is Locard's Exchange Principle?
If lifesaving action requires moving an item, the responder should do this as soon as possible.
What is document what was moved, from where, by whom, and why?
When correcting a handwritten note, investigators should generally preserve the original entry by doing this
What is drawing a single line through the error and initialing/correcting it rather than erasing it?
Close-up evidence photographs are commonly taken in two versions: one without this item and one with it.
What is a scale/ruler?
Scenario: You smell a strong chemical odor when approaching a closed room. Your safest first action is to do this rather than immediately enter.
What is stop, assess the hazard, and request appropriate specialized assistance/PPE before entering?
Scenario: An officer allows several curious staff members to walk through the scene before investigators arrive. Name the two biggest problems created.
What are contamination and loss/alteration of scene integrity?
Put these priorities in the best order: preserve evidence, ensure safety/render aid, secure the scene, begin documenting observations
What is ensure safety/render aid → secure the scene → preserve evidence → document observations?
Scenario: A note says, “The suspect entered through the window.” Explain why this is weak documentation and improve it.
It is an inference stated as fact; document observable facts instead, such as “window open, screen damaged, soil disturbed below sill.”
Scenario: An investigator photographs a shoeprint only after placing a ruler over part of it. What important photograph is missing?
What is an unobstructed close-up photograph without the scale?