First and foremost, you must have great attention to detail. Crime scenes are often chaotic, and it takes keen observational skills to spot the clues that will help solve the case. You must also be able to think logically and methodically in order to sift through the evidence and develop a coherent theory of what happened. In addition, crime scene investigators need to be excellent communicators, both verbally and in writing. They also need to be able to work well under pressure, as they are often required to work long hours in order to meet deadlines.