Crime scene investigators are called to the scene of a crime to collect evidence they hope will help detectives solve the crime and identify the criminal. Crime scene investigation is an exact science. Investigators need to be able to use many different tools and collect evidence in a way that does not contaminate it. Investigators use different kinds of tools for different kinds of crime and evidence. For example, they would bring a different kit to the scene of a shooting than they would to collect evidence from a sexual assault victim.
Every investigator's tool kit will vary, but basics include disposable gloves, crime scene tape, a hand-held magnification glass, a flashlight, tweezers, a box of swabs, paper sacks and envelopes, measuring devices, orange evidence flags, adhesive lint roller and a portable source of infrared, laser or ultraviolet light. In addition, crime scene investigators bring a camera with plenty of film (or a digital camera with memory chip), a voice recorder, a sketchpad, logbooks and pens.
A fingerprint kit is also essential for crime scene investigations. It contains fingerprint powder in different colors so investigators can ensure the powder is a different color than the surface it’s on. Powder can also be fluorescent so it will show up under infrared, laser or ultraviolet light. Investigators use fiberglass dusting brushes to apply the powder, camel-hair brushes to clean the dust from prints, clear lifting tape, latent print cards, an ink pad for taking prints from suspects, evidence seals and bags, disposable gloves and a palm print roller.
A casting kit is used for preserving footprints and tire prints. This kit includes casting compound, casting powder, a water container, a mixing bowl, mixing tools, casting frames of various sizes, rubber lifters, a fixative and Snow Print Wax spray. This last tool allows investigators to take castings in snow. A casting kit may also include an extruder gun to allow investigators to take impressions from tool marks. Some investigators carry serial number restoration fluid, which can help them determine if a serial number has been scraped off a gun or other piece of evidence.
Laser Trajectory Kit
If the investigator is called to the scene of a shooting, she will probably bring a laser trajectory kit. This helps her determine the path of a bullet or other projectile. The kit includes an angle finder, a centering cone, a laser pointer, penetration rods and a tripod mount.
The crime scene investigator also uses gunshot residue kits to determine if a suspect has recently fired a gun. Another kit has chemicals and sterile swabs to detect the presence of blood at a scene. A trace evidence kit contains many different types and sizes of containers, as well as tape lifts or a trace evidence vacuum. And a sexual assault kit will help the investigator collect and organize evidence such as fingernail scrapings, foreign substances and hair.