How to Conduct a Basic Crime Scene Investigation

Set up crime scene boundaries with yellow caution tape.

Television shows such as "CSI" and "Law and Order" have popularized forensic science and crime scene investigation. If you have developed an interest in becoming a basic crime scene investigator, colleges and universities across the United States offer associate and bachelor's degrees in forensic science. Applicants who have some education in the field are usually preferred for hire since the discipline can be very competitive. When conducting a basic crime scene investigation, there are standard steps that investigators must follow.

Things You'll Need

• Paper log
• Pen
• Cell phone
• Yellow caution tape
• Latex gloves
• Disposable coveralls
• Plastic safety glasses
• Disposable shoe covers
• Camera
• Secure plastic baggies
• Bag labels

Instructions

1. Ensure that there is no immediate threat in the vicinity to you or your team.

2. Dress appropriately to investigate the crime scene. Wear latex gloves, disposable shoe covers, plastic safety glasses, and disposable coveralls that include elastic arm and leg openings and an attached hood to pull over your head that stops any stray hairs from contaminating the crime scene. These disposable coveralls are usually made from "micro-porous polyethylene PE laminate fabric," according to The Glasgow Insight Into Science and Technology (the-gist.org).

3. Approach the crime scene cautiously to avoid contaminating it. Evidence such as hair, fingernails, footprints or traces of DNA may be present on the floor, carpeting, walls or furniture of the crime scene you are investigating.

4. Contact medical personnel for aid if there is a living victim at the crime scene. When the emergency medical technicians arrive, guide them to the victim to avoid contaminating evidence. Do not allow emergency medical technicians to clean up the scene until you have conducted your investigation. If they've arrived to the scene before you, note the team's contact information and unit number so that you can question the medical personnel at a later time.

5. Define the crime scene's boundaries with yellow caution tape to keep the crime scene secure from outsiders. Document or have an assistant document who enters and exits the crime scene at all times during the investigation.

6. Log all details of the scene in a paper log with a pen, including address, time, date, type of crime, such as murder or burglary, parties involved and any suspicious activity, including persons or vehicles leaving the crime scene.

7. Question any witnesses or bystanders who may have observed the crime taking place. Even if they weren't within view of the crime, witnesses or bystanders may have heard noises or commotion during the crime. If victims or suspects remain at the crime scene, question them individually as well.

8. Take pictures of the evidence. Important pictures may include photos of any bodies at the scene, weapons, dusted fingerprints, bloodstains, close-ups of body wounds, points of entry or exit, adjacent rooms and hallways, damage to property and any signs left behind from a struggle.

9. Place evidence that you will want to test in the forensic lab in secure plastic baggies and label each bag accordingly. Evidence may include fingernails, teeth, hair, fibers, weapons, bloodstained clothing or other items, drugs, dirt tracked in on footprints and possible tools used in the crime.

10. Document in writing any details you might find strange, such as the angle of blood spatters, any evidence that may seem to be missing and the scene's conditions upon arrival, such as a broken window or door lock. Also document any factors that may have damaged the evidence, including temperature changes, rain, snow, wind, sprinklers or animals.

11. Brief the initial responding police officer on your findings and help her control the scene by asking bystanders and others to remain away from the crime scene. Ensure that all entries and exits to and from the crime scene are still documented when the responding police officer and his team begin their investigation. According to the National Institute of Justice, you must remain at the scene until you are relieved of duty.

Tips & Warnings

• Do not pick up any evidence unless you have a partner or assistant who is clearly marking with paper flags where evidence, such as a hair follicle or wallet, was before it was picked up.

• Do not allow victims or suspects to touch or tamper with anything in the crime scene as these actions could affect your investigation. This can even include pacing on a portion of carpet or lawn where you may need to pull evidence from.

References

• National Institute of Justice: A Guide for General Crime Scene Investigation: Completing and Recording the Crime Scene Investigation
• Forensic Enterprises, Inc.; Crime Scene Investigator; Hayden B. Baldwin
• Crime Scene Investigator
• The Glasgow Insight into Science and Technology: Crimes Against Fashion - What to Wear to a Crime Scene
• Crime Scene Investigator Network: Forensic Photography for the Crime Scene Technician