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.

Medical Examination

28 03 2010


A teenager was found dead one day. The parents have no idea why their child is dead. They want to find out the cause of death and the manner of death. What should they do?



They should request medical examination. External and internal autopsies will be done to figure out the cause and the manner of death.


Medical Examination is the first thing done when the corpse arrives in the laboratory. The first thing the medical examiner does is an external autopsy; they look for clues on the outside of the body. This is done, because in most cases, what can be found on the outside can be more helpful than what can be found on the inside. Then, internal autopsy is done. The examiner looks at the internal organs to find out if he/she had a disease or damage. Many years of training in medical school must be done to become a forensic pathologist, as I said on a post that I wrote before.

First, before you start any autopsy process, you need to put on protective materials, such as gloves, eye protection, surgical clothes, etc.

Autopsy is a very complicated process, that requires a good stomach. You will be able to find a good amount of disgusting pictures if you type “forensic autopsy” on google! The autopsy always begins with a Y-incision. Next, you will remove the rib cage and expose the inner organs. You will use the rib cutter to do so. Then, you will extract some blood to use as samples for the toxicology lab.  You will poke the syringe through the heart for extraction. You will then use a technique called Rokitansky’s technique. All organs will be removed together and further dissected outside the body. Scalpel will be used to carry out this process. Then, you will need to observe the brain for signs of trauma. You will first have to expose the skull. Stryker saw will be used. Now, all necessary organs are removed. They can be now studied individually in more detail. You will weigh all organs and cut them open. Observing the organs will lead you to figure out what the cause of death is. After you figure out the cause of death, you will also have to figure out the manner of death. Manner of death is what describes how the cause of death occurred.

There are five choices

  1. Natural
  2. Homicide
  3. Suicide
  4. Accidental
  5. Undetermined

1. Natural

Natural death is sudden or unexpected death cause by disease, usually by heart disease, brain system disorder, and nervous system disorders. It can occur at any age. It is seen in 38% of cases

2. Homicide

It is death caused by another person, intentionally or accidentally. If it was accidental, it is not considered a murder. It is determined by the court. It is seen in 9% of cases.

3. Suicide

Suicide is self-caused death. Usually, suicide committers have psychological problems. It is seen in 9% of cases.

4. Accidental

Accidental death is the most common manner of death. It is used if death was unintentional or unavoidable. It is seen in 40% of cases.

5. Undetermined

Undetermined deaths are deaths that do not have certain circumstances surrounding. This is usually temporary classification until the investigation is complete. It is see in 4% of cases as their final decision.

Even before medical examination, the body can tell us many things about when someone died.

  1. Algor Mortis
  2. Rigor Mortis
  3. Livor Mortis

1. Algor Mortis

Algor mortis is the body temperature. After death, the body cools down at a certain rate until it reaches the surrounding temperature. We insert the thermometer into the liver to accurately measure the internal body temperature.

2. Rigor Mortis

Rigor mortis is the stiffening of the muscles. As time passes, the body will become stiff. Later, It will become so stiff that it won’t be able to be moved

3. Livor Mortis

Livor mortis is the discoloration of the body. Lower areas will turn dark blue or purple, because that is where the blood settles.