Step by Step

19 04 2010

I know that I have explained how investigators investigate a crime, but I wanted to walk you through the investigation step by step.

Prior to the investigation, you have to make sure you got the agreement and access to search all property and everywhere. A warrant is optional. One needs to get an warrant if he/she cannot get a suspect to cooperate.

  1. The investigation starts by observing the crime scene.
    Field kit is something that you take when you go out to investigate the crime scene. It contains impression materials, tweezers, swabs,  luminol and many other things that are needed to collect evidences.
  2. Collecting evidences
    A crime is solved by sewing the pieces of evidences together. There are evidences everywhere at the crime scene. If you just pay attention and investigate thoroughly, you will be able to find some evidences that will help you with your investigation.

    – Food as evidence
    Food can serve as an important evidence that can help us figure out the cause of death. We can analyze whether the food contains toxin or not to figure out if the food was used to sedate or poison the deceased. The food will be taken to the toxicology station in the lab to be analyzed.
    – A notepad as an evidence
    A notepad can serve as an evidence too. There might be something crucial written, such as the victim’s schedule, or there might be indented writing that has to be taken to the lab and observed under the light table.
    – Hair (or other things that can serve as DNA) as evidence
    DNA Analysis can be done to analyze the DNA left at the crime scene. It can later be compared with the suspects’ DNAs. Not only hair, but also things such as saliva, skin cell, and bodily fluid can be used for DNA analysis.
    – Corpse as evidence
    The corpse of the deceased is certainly a cruicial evidence. It can be used to figure out the cause of death and the manner of death by doing a medical examination. Specifically, pathologists will carry out autopsies. By doing an autopsy, the time of death can be estimated. The body temperature at the scene tells the recency of the death. We must look for swelling, contusions (bruises), lacerations (cuts), and bone fractures. A puncture wound shows that the victim was possibly injected with a drug or a chemical that led him/her to death. A bite mark serves as a wonderful evidence that can possibly lead to the identification of the culprit. It can be used to compare with the impression of the suspects, and the saliva on the bite mark can also be used to compare the DNA with the suspects.
    – People as evidences
    If someone hated the victim, that person is a suspect. If someone knew the victim well, that person is also a suspect. People’s DNA can be collected for DNA analysis to see if that person is who left their trace at the crime scene. Teeth impression can be collected to compare the teeth structure with a bite mark, if there is one. Comparison microscope will be used to complete such tasks.
  3. Testing the evidences
    After you collect all the evidences you want, you will go to the lab, or the morgue for the corpse, to find useful clues from the evidences.

    – Fingerprint Station
    The Fingerprint Station has the powders and chemicals necessary for processing any fingerprints. The computer has a database called CODIS with DNA information of previous suspects.
    – Toxicology Station
    The toxicology station is valuable when detecting the presence of drugs and other chemicals in substances such as blood, urine, and other bodily fluids.
    – DNA Station
    The DNA station processes evidences with DNA. They are things such as hair, blood, saliva, and sweat. CODIS is used here also.
    – Light Table
    The light table is useful when analyzing and comparing pieces of evidence in detail
    – Comparison Microscope
    The comparison microscope is used when comparing two objects. It can be used when comparing teeth impressions or fingerprints.
  4. Step 2 and 3 are repeated constantly until sufficient evidences  and clues are found.
  5. If clues are found adequate enough to surely hypothesize the culprit and how the crime occurred, the culprit is called upon and questioned.
  6. After the suspect confesses his/her crime, they are sent to the court to be sentenced.

As I wrote down the process of investigation step by step, I, once again, realized how important evidences are. The evidences start the investigation and end the investigation. I think a crime scene investigation is all about  how well you find the evidence, how well you sum them up together, and how apply the evidences to solve the crime. To become a crime scene investigator, I think the most important skill to have is finding and using evidences efficiently.

What happens at the CRIME SCENE?

3 03 2010

What do crime scene investigators do at the crime scene?

The main purpose of visiting the crime scene is crime scene reconstruction. The investigators examine the scene carefully to figure out what happened and who did it. The law enforcement officer’s ability to find relevant evidence plays a vital role on solving the crimes.

If you watch the drama C.S.I. they just take a few pictures here and there and go to the laboratory to discuss. However, it is not that simple in the real world. It is a time consuming job that requires the investigator to be alert at all times. Also, it seems like one person is doing all the job. Surprisingly, many people are part of the investigation. There is team leader, photographer, sketch preparer, evidence recorder, and many other people assisting.

When they first arrive at the scene, they first prepare to examine the case closely. They go through basic stages in the stage: they approach the scene and secure it. Preliminary survey is then driven. Then, the important part starts. They evaluate the corpse to get physical evidence and prepare narrative description. They do not just come up with one theory; they come up with mutiple theories. The photographs of the scene are taken for further evaluation, and a sketch of the scene is drawn. Detailed search is driven, then, the final survey comes. When everything is done, they release the crime scene.