After 30 hours, the body temperature begins to increase again due to decomposition. The degree of increase depends on room or outside temperature. Weather conditions need to be determined.
Eyeballs
The eyeballs usually become dry in 15 minutes of death if the eyes are open. Within 3-4 hours after death, the whites of the eyes in places not covered by the eyelids change to a brownish color called "tache noire".
Enlargement pf the black pupil area or eye dilation may be noticeable after 7 hours of death. Drugs can cause abnormal eye dilations just like some poisons. When 12 hours lapse the whole eye looks cloudy and fish-like.
Rigor Mortis
When death occurs, blood stops circulating fresh oxygen to the muscles. The muscles live even after the brain dies through oxygen left in the body. Withdrawing fresh oxygen would eventually cause the muscles to die as the muscle could no longer produce Adenonine Triphosphate (ATP) needed to process glucose and actin. Once the ATP is used up, the fibrous cells of the muscles get stuck together due to the glucose and actin. This leads to the stiffening effect called rigor mortis.
In rigor mortis, the body is limp until about 5-6 hours after death then hardness begins to set in. The following processes occur:
- stiffness in jaw -- 6 hours after death
- stiffness in upper body -- 12 hours after death
- stiffness in whole body -- 18 hours after death
- limpness returns to body -- 36 hours after death
Livor Mortis (lividity)
Livor mortis, which literally means "the color of death" pertains to the bruising of the skin caused by flow of blood into the veins due to the effect of gravity. When the heart ceases to function, the blood consequently stops flowing, and blood pressure falls down to zero. Under the effect of gravity, the blood then slowly settles of pool in the lowest-lying parts of the body. The first tell-tale signs of lividity are evident when the skin turns pale on the upper portions of the body, and a dark-red color is noticeable in the lowest-laying portions of the body.
Postmortem livity begins within one half hour after death and is set in the capillaries in 4-5 hours. Maximum livity occurs within 10 to 12 hours.
If the body is moved from its original location, you can tell by the lividity marks found in other places and not in the usual lowest point of gravity where the body is found.
You can determine if it is lividity or a bruise by pressing down the part where discoloration occurs on the skin area. If it is lividity, when you press down on the skin, the skin changes color and turns white or to the original skin color of the person because the blood is still in the blood vessels. Bruises refer to broken blood vessels. If what the marks on the skin are bruises, if you press down the part on the skin area, there is no noticeable color change.
Stomach contents
An examination of the stomach contents may help peg the approximate time of death. Food eaten in the last 2 hours is not digested; food remains 6 hours in the small intestine and 12 hours in the large intestine.
The stomach digests food and empties into the intestines at a predictable rate but some factors may affect this process. The kind of food eaten, the rate of metabolism, the use of drugs or medication, exercise and the emotional state of the person before death contribute to the speed of food processing in the stomach.
Putrefaction
Putrefaction or the process of decaying depends on several factors. It occurs slowly and is influenced by environment.
Decomposition starts in 30 hours and proceeds quickly after 48 hours. The following putrefaction processes occur in usual American indoor environment:
Within 2-3 days, a greenish discoloration is seen in the cecum and stomach. The body starts to smell.
1 week later, the body trunk turns greenish-purple. The skin slackens and falls off. Odor is strong.
2 weeks later, the skin usually blisters. The trunk turns swollen. Black fluid leaks from body openings.
3-4 weeks later, the entire body looks bloated. The face turns greenish-purple. The hair and nails fall off. Odor is overwhelming.
Right after death, microorganisms dissolve the internal organs. They create gas causing the body to balloon. The face assumes a darker hue and liquids seeps the nose and mouth. The tongue enlarges and the stomach turns to greenish-yellow color. Slowly, the skin erupts and fills with fluid or gas. If the weather is warm and humid, putrefaction occur within a day, but if environment is very cold area, it may be slowed down for several months.
Maggots
If the crime takes place outdoors, there is a strong likelihood that small animals have eaten parts of the body. Even with indoor crime scenes, insects could pose a challenge. Flies know as blow fly (Calliphoridae) lives in North America. These flies are of particular interest in homicide cases because they prefer to lay eggs on the dead bodies of humans. It is not unusual for homicide cases to find the bodies of the victims swarming with maggots (fly larvae). The medical examiner can submit them to a entomologist, to determine their age.
These insects provide scientists particularly forensic entomologist the means to establish the time of death by locating the largest (oldest maggot) inhabiting the body then measuring it in millimeters and add the number two (2) to get the estimated number of days since death.
Timeline of insect activity
10 minutes : Ten minutes after the body dies, flies arrive and lay several thousands of eggs in the mouth, nose, and eyes of the corpse.
12 hours : Eggs give way to maggots; they feed on tissues.
24 - 38 hours : Beetles swarm to feast on dry skin.
48 hours : Spiders, mites, and millipedes arrive to feed on the bugs present.
Conclusion
Establishing the time of death in a homicide is an important part in solving the case particularly if it is a case of murder and the suspect is unknown. The evidences gathered in the crime scene, witnesses and the state of the body will aid in estimating the accurate time of death.
Knowing the time of death in a homicide is a long and difficult process that requires delicate care. Due diligence should be practiced in coming up with the most accurate time of death. The methods mentioned above will aid investigators in determining the closest time. In order to be sure that no stones are left unturned and nothing is left to chance in conducting investigation and determining the time of death, the following checklist would come in handy:
- the body temperature and the degree of cooling
- look into the eyeballs
- the rate of postmortem lividity
- the extent of rigor mortis
- putrefaction
- insect activity
- examining stomach contents
