Those of you who watched the early episodes of CSI Las Vegas may remember Grissom staring at the crime scene and then saying, “How did you die? Talk to me.” His partner would then explain to the startled officers—and the viewers at home—that the scene “talked” to Grissom and helped him solve the crime. Everyone thought Grissom’s behavior was funny, made just for TV. While Grissom may have gone about things in a quirky way, he was actually pointing out something that is true: crime scenes can talk to you. In this article, I’ll explain how to use careful observation to get the crime scene to talk to you about the crime. Quoting Sherlock Holmes in The Memoirs of Sherlock Holmes by Arthur Conan Doyle, “You see but you do not observe.”

To begin with, you have to realize that a crime scene is really an accumulation of things that, when taken together and analyzed, tell the story of the crime. But in order to understand that story, you first need to find and collect all of the evidence. Here’s where careful observation comes in. Everyone’s first instinct is to ignore the big picture and head directly to the body or the central area where the crime occurred. But that kind of tunnel vision can lead you to misread the case. And if you just rush in, you risk contaminating or destroying crucial evidence. After all, the suspect had to get in and out of the scene somehow. Chances are, he or she left some evidence behind. If you pay attention, you can find that evidence.

Therefore, when you first arrive at a crime scene, you should always stop and carefully observe the entire scene before you do anything else. Once you’ve made your observations, then you can begin processing the scene. Of course, before you enter the scene, make sure you put on booties and gloves, and remember to change them when necessary. These are key steps both for protecting evidence that belongs at the scene and for preventing improper evidence from being added to the scene.

In some cases, the evidence will be right out in the open. You might see a lot of blood, overturned furniture, a weapon, etc. near the victim or in the central area of the crime. But you still have to make sure that your search is thorough; otherwise, you might miss something important. For example, I worked a case a number of years ago in which a woman was killed with a butcher knife. We collected over 200 blood samples. Out of all of those samples, only four of them didn’t match the victim. It turned out that she had cut the suspect during the struggle. When he received treatment at a local hospital, we matched his blood to our sample. That’s how we made our case. If we hadn’t conducted an exhaustive search of the scene, we might have missed the sample that led to the suspect.

Unfortunately, not all evidence will be easy to find. Fibers, hairs, dust footprints, fingerprints, etc., may be very difficult to locate. Searching for this evidence is well worth the effort, though, because it can be essential to making your case. One way to find this evidence is by looking for items that may have been touched or moved. Even if everything at the scene appears undisturbed, ask the victim or family members to check. They may notice something that is out of place. In some cases, they may even have been responsible for “straightening up” before you arrived. After all, it’s human nature to want to clean up a messy room. By asking for their help, you may find some crucial evidence. In addition, always check entranceways for dust footprints and doorframes for fingerprints. The orientation of the prints can tell you if the suspect was entering or exiting, which can be important information for your case.

Which leads me to another key point about observing the scene: it’s not enough to just gather the evidence from the scene; you have to evaluate what that evidence is telling you. Making that evaluation can be trickier than it seems. First of all, the case begins when you receive a call that a murder or a burglary or some other kind of crime has occurred. But when you get to the scene, you have to keep an open mind to other possibilities. You can’t just rush in with a preconceived idea or you’ll only find what you expect to find. Sometimes problems occur because the scene has been altered. The scene may appear “normal” or appropriate for the crime that was supposed to have occurred, but the scene has actually been orchestrated to look that way to hide a different crime.

Let me give you an example. In one instance, I was called to investigate a house that had been burglarized. The homeowners claimed that the suspect entered the house by kicking in the basement window. However, the scene told a different story. Although it had rained recently, there were no footprints outside the broken window. On closer examination, I also found that the broken glass was only on the window sill; it wasn’t inside the basement, where you would expect to find it if the window had been kicked in from outside. Clearly, the window had been broken from inside the basement. Upon further investigation, we learned that the homeowners had moved their “stolen” stuff into a storage shed. The real crime here was insurance fraud, not burglary.

Every crime scene has a story to tell. It takes years of training to gain all of the skills you need to accurately read the most complex crime scenes. But if you always remember to stop, observe, and think, you will be well on your way to understanding what your crime scene is trying to tell you.

Dick Warrington is in research and development and a crime scene consultant and training instructor for the Lynn Peavey Company. For the past several years, Dick has been teaching classes throughout the U.S. and Canada, trying to dispel some of those “you can’t do that” myths.