What is a "Crime Scene"?
A crime scene can be anywhere a crime took place, or anywhere evidence relating to that crime is, or may have been. For these scenes, evidence may be anything that helps reconstruct events, or connects a person to a scene, item, or another person.
In short, crime scenes can be anywhere, and evidence can be anything, depending on your case. You must ensure the forensic investigation is thorough, and overlooks nothing at the start!
What's First at a Crime Scene?
A crime scene can look like many things, but one consistent aspect are the priorities that exist.
The first priority at all crime scenes is always the same. That is above all else, priority is given to the preservation of life! Not preservation of evidence, as many may think, because that is a secondary priority to the preservation of life. This means the lives of anyone in the scene, and the lives of anyone investigating or processing the scene must be given precedence over the evidence.
With that priority remaining in the forefront, what comes next is securing the scene, to preserve any evidence that may be present, and obtaining legal authority to search for, and seize evidence from, that crime scene. This is always were you must begin at a crime scene.
How Many People Are Needed to Handle & Process a Scene?
There is no set number, and each scene is unique in what it requires, but a team approach is always best. Especially for larger or more complex scenes, you will need a variety of people doing a number of different tasks.
Nevertheless, to limit contamination, it is imperative to minimize how many have access to the scene, and to secure the scene as soon as practicable. Processing a scene takes time, and often a lot of time!
No one person can be an expert in everything, unless you're an actor on TV ;). We all need support and a second set of eyes. Ensure any expertise needed at the scene, is a part of the team. Police, Fire, EMS, and any others need to work collaboratively to maximize both the scene safety and the evidence you may recover while processing a scene.
What Personal Protective Equipment (PPE) Do You Need?
You must continually evaluate what PPE to use based upon the potential threat from the scene to you, and the threat from you to the evidence.
The most common PPE are gloves (medical grade), footwear covers, and tyvek suits (A60). However, at times, additional forms of breathing protection in the form of respirators or self-contained breathing apparatus may be required.
You must understand the threats before you go in, and always begin at the highest level that may be needed for the scene!
The two most basic types of threats are:
threats from scene (biological, chemical, explosive, etc.) to you, and
threat of you (contamination, destruction, etc.) to the scene!