Strings of police tape fluttering in the wind, police vehicles littered about and empty streets. An officer standing guard clutching a mysterious green book, an army of equally mysterious white clad people carting around evidence bags and a news helicopter buzzing overhead. Sounds like you’ve got yourself a crime scene…
Having been that solitary officer many a time and having spoken to members of the public whilst I’ve been rooted to the spot for hours on end, I know how interesting crime scenes can appear and think I understand a little why members of the public are so fascinated by our presence at them. Has there been a grizzly murder? Are they digging up skeletons? What is going on?
For the most part crime scenes are not perhaps as interesting as they might appear and whilst we’re not really able to discuss why they’ve been designated as such when we’re there, I think often the explanation may often be a little disappointing. I’ve stood on scenes, for example, in which large areas have been cordoned off to preserve the tiniest specks of blood or even, in the case of rape scenes, evidence that may not even be visible to the naked eye.
Why do we establish crime scenes then? Put simply the aim of a crime scene is to secure and preserve forensic evidence. When a serious incident has occurred at a location we are sometimes required to restrict access to that place, or part of that place, so that any clues explaining what has happened are not lost or disturbed. Often it’ll be unclear exactly what has happened – we’ll arrive to find two wounded parties and will need to establish a crime scene securing the evidence inside it to help prove or disprove the accounts given by each of those involved.
Having set up the scene specialist departments are likely to come and visit to collect the evidence itself. Detectives may want to survey the scene, forensics experts might need to take photographs or samples and specialist officers may need to conduct a thorough search e.g. to locate discarded bullet casings from a firearms incident.
To maintain the integrity of the scene we restrict who can enter it. This is where the mysterious green book comes in to play. This is a scene log and we use it to record the details of everyone attending and why where were there. Having made these records we are able to account for the integrity of the evidence closed inside the sealed area. In the simplest terms this means in court we can say in confidence that say a blood stained knife found at the scene was indeed found at the scene and has not been tampered with after the incident took place as no one has had the opportunity to do so.
Crime scenes are kept ‘open’ for as long as it takes to gather the evidence. For a small incident this could be for an hour until photographs have been taken whilst for a larger incident such as the recent shooting in London, a scene may not be closed for several weeks.
Contrary to what some people may think, guarding an outdoors scene at four o’clock on a cold winter’s morning is hardly the best way to spend a shift but it is important nonetheless and very much part of our job. We’re probably not inside drawing chalk outlines around multiple bodies laid out to spell the words ‘you’re next’ but even so, what we will be doing is gathering evidence to give us the best chance of getting a conviction in court.