Any experienced crime scene officer will tell you that the key to doing the job well is protecting the crime scene. What does that mean? In a nutshell, it means securing the scene, limiting access to only essential personnel, and keeping complete and accurate records of everything that happens there. These steps require work and diligence on your part, but your effort will pay off when you end up with high quality results that will stand up in court.

As you know, the first person on the scene should secure it. However, the first officer on the scene is often confronted with many challenges, especially when dealing with a major crime. Before securing the scene, the officer must establish priorities. For instance, if the officer finds victims needing medical aid, the officer must first provide assistance and call for help. At the same time, the officer must be alert to the presence of suspects and deal with them accordingly.

Once the victims and possible suspects have been taken care of, the first officer can focus on the scene itself. After getting everyone out of the scene, the officer must secure it and prevent anyone from entering. The first officer should also call for a search warrant so that crime scene officers can search the scene and collect evidence. With the scene properly secured, a search warrant can be obtained if needed.

Think carefully when you secure your scene. Keep in mind that it is always better to secure a larger area than you need. You can always shrink the perimeter once you begin processing, but you can’t expand it. In fact, if you do extract evidence from outside of the area you originally secured for your scene, that evidence will be considered questionable in court. After all, who’s to say that that evidence was there when the crime took place? The last thing you want is to have evidence thrown out because you didn’t do your job right. Better to be safe than sorry.

Once you establish the outer perimeter of your scene, you need a way to secure that boundary. Everyone uses crime scene tape for this job, but tape doesn’t necessarily stop people from entering. You should also have officers stationed around the perimeter of the scene to make sure unauthorized people don’t enter. And of course, the larger the scene, the more officers you’re going to need, so plan accordingly.

Remember, the key to preserving the scene is limiting the people who come in and out of it. Often at major scenes, everyone from the general public to the press wants access. You may even have officers and other officials who don’t have a role or job to perform but want “to take a look” for curiosity’s sake. The more people who enter and leave the scene, the more chance you have for contamination. And anyone who enters a crime scene could potentially be subpoenaed. Ask yourself if the people present really need to be there. Then do your best to allow only the essential people in.