Fire investigation, sometimes referred to as origin and cause investigation, is the analysis of fire-related incidents. After firefighters extinguish a fire, an investigation is launched to determine the origin and cause of the fire or explosion. Investigations of such incidents are done using a systematic approach and knowledge of basic fire science.

Fire investigation is one of the most difficult of the forensic sciences to practice. In most forensic disciplines, even the basic question of whether a crime has been committed is normally obvious. During a fire investigation, an entire process must be undertaken just to determine if the case involves arson or not. The difficulty of determining whether an arson fire has occurred or not arises because fires destroy evidence.

A fire investigator looks at what is left behind after a fire and obtains information to piece together the events that occurred in the moments leading up to the fire.

One of the challenging aspects of fire investigation is the multi-disciplinary base of the investigator’s job. Fires can be caused by or involve most things people see or use. For this reason, fire investigators need to know not only basic science of fire behavior, but knowledge of many different areas of study (including construction, electricity, human behavior, vehicles etc) is helpful. If the fire origin has, for example, a gas appliance, an investigator should know enough about appliances to either include or exclude it as a possible cause of the fire. Fire investigators must also know their own limitations and call upon experts to assist when needed. Accordingly, fire investigators sometimes work with forensic electrical engineers (when examining electrical appliances, household wiring, etc.) or others skilled in forensic engineering (gas-powered appliances, air handling equipment, gas delivery systems, etc.).

Decomposition refers to the reduction of the body of a formerly living organism into simpler forms of matter. The body of a living organism begins to decompose shortly after death. Such decomposition can be simplified in two stages: In the first stage, it is limited to the production of vapors. In the second stage, liquid materials form and the flesh or plant matter begins to decompose.

There are environmental influences that will affect decomposition. A body that is exposed to air will decompose more quickly and will have more insect activity. A buried body will decompose eight times slower than a body exposed to air. This is due in part to limited insect activity and possibly lower temperatures. Likewise a body submerged in water decomposes at half the rate of an exposed body. The rate of decomposition depends on the temperature of the water. Cold water will allow slow decomposition and warm water causes faster decomposition. The body is also shielded from insect activity as long as it is submerged.

A latent fingerprint is an example of a two-dimensional impression. A footwear impression in mud or a tool mark on a window frame is an example of a three-dimensional impression. If it’s not possible to submit the entire object containing the impression to the crime lab, a CSI makes a casting at the scene.

A casting kit might include multiple casting compounds (dental gypsum, Silicone rubber), snow wax (for making a cast in snow), a bowl, a spatula and cardboard boxes to hold the casts.

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Forensic art is a law enforcement artistic technique used in the identification, apprehension, or conviction of wanted persons.  Forensic art encompasses several disciplines including composite art, image modification, age progression, post-mortem reconstruction and demonstrative evidence. However, composite art is traditionally the most commonly known discipline of forensic art. The art of composite drawing has been used by police agencies throughout history. When one recalls the Old West, the classic wanted poster with a drawing of a “Bad Guy” comes to mind. These drawings were composites.

Composite Art is an unusual marriage of two unlikely disciplines, police investigative work and art. The cop-artist, almost an oxymoron, possesses both skills. The artist can create a quality facial drawing with assured confidence. Though drawing skills are important parts of composite art, the real challenge is in the ability to interview and relate to a victim or witness. The purpose is to successfully gather, interpret and illustrate the information obtained from the victim’s memory.

In the past twenty years, the discipline of composite art has evolved into forensic art. The forensic artist possesses knowledge of victim psychology, post-mortem reconstruction and human aging. These artists currently use new computer technologies and digital imagery to create more successful investigative images.

Point of Impact / Point of Origin

Point of impact is the point of which some object strikes a bloody source. Point of origin is the three diamentional area where a bloody object is struck.

Shadowing and Ghosting

Shadowing and Ghosting occur when blood is sprayed around a room and there is an intervening target.