So What Did Margie Say About...the CSI approach

Because there was no Bones episode on 5/13/13 I'd like to talk about how crime scene investigators approach a crime scene utilizing observation and perception.

 

Investigators should record their observations using their five senses: what they see, hear, feel, smell, and, to some extent, taste.  A heavy sulfur atmosphere will combine with smell and give a hint of a twang taste.  Lots of fresh liquid blood will smell and give a slight taste of iron.  

I am not saying that one actually taste these things by placing something in your mouth.  If you just open your mouth and breathe the air you can get the "sense" of taste when nothing blocks your smell.  Some people use something in their nose to block smells but this practice may also mean that you may miss some information.

 

Obviously one records what they see but sometimes what you feel or hear is important too:  Is it a cold environment?  Is it humid?  Is the wind blowing?  Is the heat or air conditioner on and working?  Do you hear engines or machinery?  Is there water dripping in the scene?  Is the body warm to the touch? 

 

Do you smell anything?  Is the smell common to the area?  Is the body in a state of decomposition?

 

These observations are altered by your perception.  Depending on your training, your life experience, and your background on the job, you may perceive things differently from someone else with a different history.  

I have heard the tale of a law enforcement agent and a fireman at the scene of a homicide followed by an arson.  The law enforcement agent gravitated toward the evidence of a cartridge case located on the floor.  The arson investigator gravitated toward the book of matches next to the cartridge case.  Same scene, same area but a different point of focus because of their backgrounds and interests. 

 

This is why at the end of a crime scene response, it is advisable to get what is called a "fresh set of eyes" to reevaluate the scene.  One reason is that they will have a different perspective and may find something that the original investigator did not focus on.  The other reason is that after many hours on the scene, you are tired and a fresh viewpoint will help to assure that the best job was done.