How to Do a Crime Scene Investigation
On TV, it looks easy--even glamorous. Model-perfect investigators sweep over crime scenes, hair flowing in the wind, designer jeans bending over the victims. And there's never a shortage of back-up help to process the scene. In reality, the gritty world of crime scene investigation requires immense patience and a passion for detail. Observing and collecting minute clues can be a laborious, tedious process that can't be rushed if evidence is to stand up in court. If you're a fan of crime stories, you probably already know how some professionals do their jobs, so consider this article Crime Scene 102.
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Things You'll Need
- Evidence collection kit (supplies and tools)
- Digital camera with back-up batteries and memory cards
- Notebook, sketchpad, writing instruments
- Disposable HAZMAT suits and caps
- Gloves
- Protective eye wear
- Foot covers
Instructions
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Appear at the crime scene immediately after getting the call to preserve it. Upon arrival, cordon off as much of the surrounding area as possible without blocking traffic by using yellow vinyl warning tape. Station law enforcement officers around the perimeter to keep out sightseers and other unauthorized people. Request the presence of a law enforcement communications specialist to deal with any media arriving on the scene as a result of the incident being broadcast over the police radio band.
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Suit up to protect the scene from contamination, and to protect yourself from inadvertently coming into contact with blood-borne contaminants and other matter. If there's a chance of unexploded ordnance or other danger, don't enter the area until a specialist has diffused the situation. Once you get an all-clear, walk the crime scene from all angles to get a general idea of the environment in which the crime took place. Look for the positioning of bodies, blood splatter patterns, tire track marks and other telltale signs. Begin photographing all aspects of the scene.
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Place plastic markers at the site of each piece of evidence. Use a notepad to record what you found, annotating each item with the corresponding marker number. When everything has been photographed, noted and accounted for, use bindles, bags, laboratory jars and containers to collect each piece of evidence. To keep the items free of contamination, use chain-of-evidence protocols. Record items in a central log before transporting them to the crime lab.
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Attend to the body if the investigation involves a homicide. Resist the urge to cover the body. If you touch the victim's skin, clothing or other surfaces--even to place a blanket or cloth over the body--you will likely contaminate it by adding dirt, soil, dust or other environmental elements. Once the medical examiner arrives at the scene, she will take additional photos, and a forensics thermometer will be used to estimate the time of death. This is just a cursory examination. A full exam will be done in conjunction with an autopsy at the morgue.
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Begin to canvass the area once the body has been removed and the evidence has all been bagged, tagged, cross-referenced and transported away from the site. Use your badge, press card or other credentials to open conversations and question passers-by, people in the area and those familiar with the deceased if a murder is being investigated. Hand out business cards to those you interview so they can contact you at a later date with additional information. Wrap up the scene. Remove the protective clothing you're wearing, take final photos of the area and leave.
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Follow up on delivery of the items gathered at the scene to make certain everything has been logged into the evidence area according to protocols. Some investigators may ask to be present at autopsies if they're to be involved in an ongoing homicide investigation. Still others may wish to follow up with forensics technicians to get help with their investigations. Some of the specimens gathered will go to "trace evidence" analysts. Others will be sent to DNA experts, or to an outside lab if there are no professionals or equipment on hand to handle this important aspect of the investigation.
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Tips & Warnings
Some crime scene investigators are trained to sketch. Others use sketch artists on site to supplement photography. Many law enforcement agencies provide a packet of crime scene forms to investigators with specific directions for completing each step so nothing about the site is overlooked.
Crime scene analysis looks fast and furious on TV, but that's because producers have only an hour to tell each story. In reality, some labs are overwhelmed by evidence, and understaffed, so it could take weeks or months to analyze evidence, unless pressure is applied by higher ups to move the case ahead.
References
- Photo Credit © Staffordshire University Forensics, UK
