Believe it or not, figuring out  the time of death for a dead body isn’t an exact science, nor is there one thing an investigator can observe to give a truly accurate time. Rather, it’s only through a collection of many observations that can provide insight into the time of death.

Rigor Mortis

Rigor mortis occurs within 1-3 hours of death and is characterized by a stiffness of the body. While the process is not totally understood, we know that it starts with the smaller muscle groups and works it’s way up to the bigger ones. It starts at the jaw, moves to the elbows and then to the knees and then, and only then, is a body considered to be in full rigor. The chemical process of rigor mortis is irreversible.

Livor Mortis

Livor mortis normally occurs within 8-10 hours after death and is characterized by a discoloration of the body. This is due to the gravitational settling of the blood, which is no longer being pumped through the body by the heart. While this discoloration might be almost immediately apparent (within 20 minutes – 1 hour), the intensity of the discoloration greatly increases within that 8-10 hours I mentioned earlier. The formation of livor mortis may be hindered when pressure is applied to a certain area. For example, if a body is lying on its back, pale areas may be present on the shoulders, the buttocks and the calves.

Algor Mortis

Algor Mortis is a cooling down of the body. Normally, at least in ideal conditions (a 70 – 75°F environment), the body’s temperature equalizes itself with it’s environment within the first 10-12 hours after death. Obviously every dead body isn’t going to turn up in the ideal environment, so other variables have to be taken into consideration. Location temperature is definitely one thing to consider, but body fat and clothing type are other things. Body fat and heavy clothing store heat longer and therefore cause the body to cool at a different rate. Another thing that sometimes leads to erroneous algor mortis calculations is that it’s almost always assumed that the person’s temperature was the typical 98.6°F when death occurred, but several other factors could be in play here as well: fever, drug use, physical exertion or pretty much anything else you can think of that would raise someone’s body temperature, or even cool it down. The proper use of algor moris in determining time of death relies heavily on realizing it’s limitations and taking into account other observations.

Gastric Contents

In other words, what someone ate. If a body was found in the evening and only had breakfast type food in the stomach, a reasonable conclusion would be that they died in the morning or very early afternoon. If the time of the person’s last meal is known, looking at the stomach contents and digestion tracts would enable investigators to narrow time of death because of the rate of digestion, however it should be noted that persons under duress, physically or mentally, may have slower digestion rates. Another important aspect of this to consider would be in finding out where the food in the stomach came from. It could be that the person ate something that is particular to a specific restraunt, which may help nail down when and where the last meal was consumed and with whom.

Crime Scene Investigation

This is where the life stages of certain insects are helpful. An entomologist may be brought in to study these insects because presumably, they have a predictable rate of life and death themselves. Plant biologists are helpful here as well because they can analyze specimens found on the clothing and gastric tracts just to name a few. They look at at twigs, leaves, roots, pollen, fungi, algae, etc. to determine if the body had been moved and it’s origin. Things not associated with the body can also be used to determine time of death such as mail and newspaper pick up, the lights or television on, the sort of food that was being prepared, etc., etc.

Decomposition plays a huge role in all this as well, but since there is so much information to convey on that one area, I will do it in next week’s post.

For those of you who missed the last mystery I posted, I will give you another chance to win 2 hours of my time in helping you set up a WordPress blog either on WordPress.com or your own domain – or even still, if you already have one of those, I’ll help you optimize it – by solving a mystery using the “How To Determine Time of Death” posts when I finish them. I’m doing this to create some interest in the NF book I’m currently working on that has to do with that very thing. So, until next time, happy killing! Fictionally that is…