Crime Scene Investigation Skills

Crime scene investigation skills are an invaluable part of any policeman's job. They entail the ability to notice small details, to make intuitive leaps and to ferret out important pieces of evidence from an ocean of incidental details. A successful crime scene investigator will be able to deduce what happened at the scene with a fair amount of accuracy and provide solid evidence that is admissible in court. A poor one will overlook important details, bury solid facts behind inconsequential trivialities and even destroy important evidence through mishandling.

Basic Abilities

The most fundamental skills involved in crime scene investigation are those that can't be taught--a good investigator is born with them. A good investigator has the ability to notice things--to take in the totality of a given room or space and identify as many pertinent details as possible. This includes obvious crime scene elements like bloodstain patterns or the marks used on an open safe as well as more subtle elements like an off-kilter picture in the house of a compulsive neat freak or a brand of cigarette in the ashtray that no one in the household smokes. A good memory can serve the investigator well too, allowing him to conjure up details of the crime scene after the fact at a point when they may be useful.

Scientific Skills

Formal scientific skills are equally invaluable when investigating a crime scene. This includes a knowledge of forensics, biology, anatomy and chemistry. It can involve identifying different types of dirt, the caliber of handgun fired, the way different poisons work on a human body and the type of patterns glass makes when it breaks. It entails a familiarity of the various chemicals used to locate evidence (fingerprint kits being only the most obvious example) and the effects they have on the surrounding crime scene. The investigator must also have a good knowledge of photography in order to document the scene accurately and understand how to use forensic equipment such as UV lights. Some of this can be learned in university courses while other skills can be learned at the police academy and as part of on-the-job experience.

Careful Preservation

Evidence gathered at a crime scene is extremely important and needs to be handled in a way that preserves it for later study (and possible presentation in court). Accordingly, a crime scene investigator must be able to gather it with the utmost care. In cases where it must be put in an evidence bag, he needs to do so without contaminating it or marring its surface. Fingerprints need to be preserved until they can be compared with a proper database while bloodstains, dirt stains and bullet casings must be stored for future examination. In some cases, the investigator must climb up to a ceiling or maneuver around tricky corners in order to properly retrieve some tiny detail. And because a great deal of crime scene evidence is circumstantial (i.e., able to connect a given suspect to the location but not able to directly implicate him), it must be held safely for months until it can be presented in court.

Law Enforcement Basics

In addition to specific crime scene skills, most crime scene investigators must maintain the same array of skills that any other law enforcement officer does. This includes physical fitness, knowledge of firearms, an understanding of the law as it applies to her job and a familiarity with the specific policies of the department she works for.

Thorough Accounting

Many policemen complain that the biggest part of their jobs is the part that no movie ever shows: the paperwork. This is doubly true when investigating a crime scene. Each and every detail needs to be cataloged in a report, stating where it was found, what condition it was found in, how it was retrieved and what bearing it may have on the case. Such reports are important because they may come into play later during a trial--long after the initial details have faded and dozens of other cases have been investigated in the interim. A crime scene investigator will file his reports thoroughly and accruately as soon as he is able to in order to better preserve the fresh impressions of the crime scene.