I attended a session at Killer Nashville presented by Sgt. Derek Pacifico, a retired homicide detective called An Overview of Homicide Investigations. It was eye-opening. In fact, I learned that I’ve done a lot of things wrong in my writing about detectives and the way they approach crime scenes.  I hope these 8 lessons learned will help you as much as they will me!

Lesson 1 – The first person on the scene.

A patrol officer is almost always the first person on the scene.  Guess what?  They cannot pronounce death. Even in obvious cases of death. That’s not to say they’re not capable of telling when someone is dead. In some cases, it’s pretty obvious.  However, legal guidelines exist to determine who has the authority to pronounce death – usually someone with the medical examiner or coroner’s offices. The patrol officer’s just is to secure the scene until the appropriate people arrive to move the investigation forward.

Lesson 2 – The perimeter around a death scene is much larger than you might expect.

According to Sgt. Pacifico, “the rule of thumb is to determine the actual size of a crime scene and then to double the containment area.” In some cases, the containment area – the area blocked by off by barrier tape – can be even larger than that. He used the example of a homicide inside a house.  For investigative purposes, Pacifico said he has cordoned off an entire block, because you don’t know where the perpetrator has been, therefore you want to preserve all possible locations.

Lesson 3 – Processing the scene of the homicide takes MUCH longer than you think.

Consider the details of processing a scene. The first responder call detectives out.  They arrive with a crime scene investigative unit. The scene has to be examined, and cataloged inch by inch. That means there are multiple layers of examination to do, and every item deemed important in every layer needs to be photographed and properly preserved. In some cases, it could take hours (or longer) to even reach the body.

Lesson 4 – Once the scene is secure, no one except the homicide detective and the crime scene unit crosses the barrier.

It’s true. Not even the Sherriff can cross the barrier tape into the crime scene until it’s cleared by the lead detective. In reality, no one else WANTS to go into the scene, because if they do, then they are likely to have to testify if the murderer is caught and convicted, and most law enforcement officers hate testifying.

Lesson 5 – The medical examiner is usually not the person that shows up at the scene.

I’m sure there could be circumstances in which the medical examiner might respond (such as in a small town), but in most instances, it’s a deputy coroner that comes to retrieve the body.  Furthermore, they don’t respond immediately in most cases.  As Sgt. Pacifico explained it, the coroner’s office is called early on, just so they can add the crime scene to their list of things to do.  The coroner’s office has to respond to all death’s that happen outside the hospital, whether there are suspicious circumstances or not.

Lesson 6 – Homicide scenes generate thousands of pictures.

Documenting crime scenes requires thousands of photographs.Everything is photographed, often from different angels and distances. In the processes of photographing a scene, the photographer uses a scale – which is like a ruler – that is either white or gray and often has a level on it to ensure the pictures are taken at the right angle. The scale has the photographer’s name printed on it for identification purposes. The photographer also sometimes takes duplicate pictures with a second camera as a backup. Included in these thousands of pictures are photographs of the bottom of the shoes worn by every person that enters the crime scene.

Lesson 7 – Time of death really doesn’t matter all that much.

It makes good television and book drama, Sgt. Pacifico says, but the truth is, time of death isn’t all that necessary to solving a homicide. He couldn’t remember a single case during his career when time of death had been a factor in determining the murderer. There are many other pieces of evidence involved in solving a homicide, and it’s usually those pieces of evidence that lead to the perpetrator.

Lesson 8 – Well-meaning citizens are a pain in the ass.

People who aren’t trained in the science of crime scene investigation don’t know when they’re doing something wrong.  For instance, Pacifico showed a slide of a body covered with a blanket. It was put there by a well-meaning citizen that was just trying to “protect” the evidence.  However, the blanket was one used to protect car seats from dog hair.  It transferred that dog hair (along with all manner of other trace evidence) to the victim.  All of that trace had to be ruled out, which increases the work load of the team trying to solve the homicide.

I learned much more, but these are the bits that I thought you might find most interesting.  If you have questions about any of this, please post them below.  I included just the basics in an effort to keep this to a semi-reasonable length.