I'm referencing the handouts and class presentation used by my co-presenter at the NJ SCBWI for our workshop Scene of the Crime: How Experts Handle a Crime Scene and How Authors can make it Real. Besides his extensive experience as a forensic crime scene detective, he used the following resources:
1- The Manual of Detection by Jedediah Berry
2- http://coldcasesquad.blogspot.com, by Joseph L. Giacalone, ret. NYPD Det.
I'll give you a brief rundown of the basics of forensic crime scene procedures and common mistakes that writers make.
Processing the Scene1. Secure and protect the scene. This means except for the crime scene investigator and emergency medical people, no one should go walking through the crime scene, not even other police officers.
2. Initiate preliminary survey. Check the scene, look for visual clues.
3. Evaluate physical evidence possibilities. Does it look like more than two people (victim and perpetrator) were involved. If gunshot, was there more than one? Is there a murder weapon?
4. Prioritize collection of evidence. Safety first: are there weapons that need to be secured? Is there evidence that could get contaminated?
Guy poses the following questions that crime scene detectives ask:
a- Did the homicide, assault, etc. occur in this location? What happened here; was there a fight, signs of a struggle? When did it happen and what types of evidence should there be?
b- Has the body been moved by either family members, first responders like EMTs, someone else?
c- Has any object been moved by others?
d-Was a gun/rifle used? What type of weapon (automatic, revolver, etc.) More than one shot in victim, possibly lodged in walls, etc.?
e- Are there shell casings?
f- Is there blood spatter?
g- Is there blood in other rooms?
h- Are there visible footprints or fingerprints in the blood?
i- Is all evidence visible in photos taken at scene and properly numbered and logged?
5. Prepare a narrative of the scene. CSIs take notes and start to tell the story, based on evidence, of what they think happened. Because of the length of time it may take to go to trial (months to years), these notes must be precise. Just the facts, ma'am, and no guesses. (Guy notes that in NJ, a detective's notes must be submitted as evidence.)
6. Capture the scene photographically. Include long shot, close-ups, and medium range shots with measurement scales (rulers) and numbers.
7. Prepare the crime scene sketch at the crime scene. This rough sketch is used to document measurements and placement of evidence. A more detailed sketch will be prepared later.
8. Conduct a detailed search. Broaden the area beyond where the body lies.
9. Record and collect physical evidence. Evidence must be secured, uncontaminated and properly documented and packaged from the time it is picked up until locked in evidence storage. This is called "chain of evidence." Anything with blood or other fluids cannot be placed in a plastic bag because that hastens decomposition (hence all the brown bags you may see on documentary investigative shows or the news.) The proper packaging must be used depending on the type of evidence.
10. Conduct a final survey. Make sure all the evidence is collected by walking through.
11. Release the crime scene. No one, not even family, should be granted access to the scene until the detectives are finished with their investigation.
Being aware of the following procedures should illuminate why such shows as Murder, She Wrote (Guy used this example) is just pure fabrication. Realistically, no outsider is allowed to tramp through the crime scene or get near evidence. Stay behind that yellow tape!
Till then, stay out of trouble!