Estimating the time of death for the deceased is something else that the pathologist will have to do during the course of his autopsy procedures. In addition to this he or she may be called upon at the scene of a crime whilst carrying out their external examinations to try and judge - or best guess - when the victim died.
At the Scene
It may sound silly but one of the first things to do once a crime scene has been secured and all relevant details documented; is to check for a watch. If the victim does have a watch is it broken? If it is then the watch will more than likely have stopped at the time of the individual's death, especially if they have had a heavy impact or long fall.
It must be said however that the time the individual took their last breath is not necessarily the time at which they died. This may sound bizarre but taking into consideration the human body can function for a period of time without oxygen - the human brain reportedly surviving several minutes without it - then it is reasonable to assume that the time of death may not always be accurate.
Categorising Time of Death
Time of death is categorised in three ways:
Physiological time of death: The point at which the deceased's body - including vital organs - ceased to function.
Estimated time of death: A best guess based on available information.
Legal time of death: The time at which the body was discovered or physically pronounced dead by another individual. This is the time that is shown - by law - on a death certificate.
One method of estimating the time of death is to measure body temperature. The normal equation for this is:
37.5oC - 1.5 oC
This formula equates to the body temperature (37.5oC), which loses 1.5 oC per hour until the temperature of the body is that of the environment around it; known as the ambient temperature. This ambient temperature - depending on how low it is - may take minutes or hours to be reached and this is a good indicator as to how long a body has been in situ. Additionally it is worth noting that a body's temperature will drop much more slowly if the body has been exposed to extreme cold; such as being left outdoors, submerged in water or icy conditions.
The most common way of taking the temperature of the deceased is to use a rectal thermometer or to take a temperature reading from the liver, which can achieve a more realistic core body temperature.
Rigor Mortis also acts as a good measuring stick for estimating the time of death. This natural process which occurs in all of us when we die and is the natural contracting and relaxation of the body's muscles caused by changes in the body's chemical balances.
Rigor normally occurs in the smaller muscles such as those in the face and neck and will work its way down through the body as the muscles become larger. The process normally begins roughly two hours after death and can last for anything from twenty to thirty hours. It is a common misconception that rigor does not leave the body; it will after these time frames have elapsed.
Rigor is one of the most used ways of estimating death as it occurs in the body during the first thirty-six to forty-eight hours.
Forensic Entomology (the study of insects) is another way in which the time of death can be estimated. By studying the insects found at the crime scene the pathologist is able to establish a more accurate time scale depending on which insects are found on the body and what stages they are at in their life cycle. To find out more read our article on Forensic Entomology.
I recently lost my Mom. She was alive when I left at about 12pm and when I came back and found her at 3 she was gone and her head was cold to the touch. I keep thinking she may have died after I left but no one will tell me anything. I'm just sick about this.
Mandy - 11-Jul-16 @ 6:41 PM
I while with US Intel was called to the scene on the Texas Mexico line . It was 103 Degrees that day Rigor set in 70 min or less a on quick exam I fond needle marks
On his two feet. I concluded the death by.drugs .I was correct when injected in both feet it covers the body
Doc - 5-Jun-16 @ 8:19 PM
One must never forget to check air temperature at body's location. be sure photos have finished before moving or turning body . If body covered it will effect. The temperature and time of death as well as rigor.never forget trauma signs if seen. Body temp uncovered in mild air temperature will lose 1.6 degrees however this must be determined by the environment of ait temp.and coverings on body depending on air temperature. This can either speed or decrease body temp.the old check there watch isoutdated in today's watches.
Doc - 30-May-16 @ 7:31 PM
In extreme heat Rigor can occur in 75 min
Dr Rick Breazeale PhD forensics.
Doc - 30-May-16 @ 7:03 PM
Only serious responses please. Early spring I unfortunately found my sister (late 30's) had unexpectedly passed away.I saw her in the middle of the night, passing her in the hallway.Later that day I had spent several hours outside the house doing yard work and had truly never realized that she had not gotten up for the day, she does a lot of her computer work from her room, so sometimes only leave her room when working just to grab a bite to eat or to "relieve herself'.At dinner time I knocked on her door, no answer, opened the door and found that she had passed at some point that night/day.I believe from what I have been able to read that she was either in full rigor, or very close to it.I wasn't in a very good condition to check much of anything besides the knowledge that she had passed.She was laying on her stomach, and I turned her stiff body over and her arm remained in stiff place, and there was presence of the "purple blood pooling" on her stomach area and her face was "cool to the touch".There was an autopsy done, however due to me providing them with a fairly close time line as to when I last saw her, they did not do a "liver temp test" or anything like that.Several times throughout the day I have the guilt of not going to her and dragging her outside in the nice weather, but in the end I left her be.I guess i need to know (and I know nothing is written in stone) but approximately how many hours had passed since she had passed away.Was it closer to 3 hours or 12 hours, (3-12 hours is a HUGE window) it makes a big difference in the guilt of not checking on her that day.I cant get past the guilt that maybe something happened that maybe I could have helped had I checked on her.
Cass - 16-May-16 @ 6:39 AM
my father was found on feb 10th last heard from by aunt on jan 31st step mom supposidly left jan 28th with both sets of house keys and her grandson had cops check on my dad 9 days after 31st and found dead but his dad said they spoke every other day and step mom opt for no autopsy can ashe remains be tested
joy559 - 11-May-16 @ 2:03 AM
I think we are not doing due diligence here.
All chemical makeup,
In the body, what organ, how much,
After the body is dead.
Food, pesticides, soaps, cleaners, gas fumes from cars.
All needs analyzed.
You are telling me we can't create taxes to keep freezing all our bodies, save them. So that one day we can get all chemicals that. Break down our body, find a reversal to heal it, move time backward.
All things can be figured out.
Minerals, coal in caves, rubies under New York churches, analyze, quantitate it all.
I don't eat meat. Don't like it.
I see animals as humans.
We can't measure it all?
Rice is now an arsenic concern.
We should be able to quantify it all and live forever.
Suffering is just not right ever.
It just isn't.
Bless you all.
I don't believe in God , from what I be read some stoning violent credo was taught, and that just is not healthy to teach to no one.
People that like it obviously sick in the head.
Frog - 9-May-16 @ 12:17 AM
Ted Cruz is the Zodiac Killer.
ChoppMan Eddie - 22-Apr-16 @ 7:16 PM
I have been in that situation and found a friend passed in there sleep several hours after death they gave an approximate time of death and it was 3 days she had been there within hours or so it's not a nice experience and there are people to help you cope with shock
Tina - 29-Mar-16 @ 10:57 AM
I found a dear frienddead on his bed today (Thursday 24th March 16). I found him at approximately 7pm on the Thursday and I was the last one to see him alive at 10pm the previous evening "Wednesday "so 21 hours had passed... when the police arrived and they were the first services to arrive on the scene an hour after my call... the rolled him from his back as he was laying on to his side to inspect his back/body and his leg and arm stayed firmly in there position up in the air and did not from rigamortice had well set in... but is there any way of getting a time of death to the nearest hour/hours I knocked his door a few times during the day with no answer but he suffered with kidney failure and I guessed he was at the hospital having his treatment... I was wrong... please help
wayne - 25-Mar-16 @ 4:36 AM
This is helpfull my greatgrandma is dying and they said on the 22 of feb or the 23 of feb she would probably be dead (crying) I dont want her to die on my birthday!!
Kaite - 21-Feb-16 @ 5:22 AM
Are you sure your mom was already deceased? 28th warm tempratures as she has?
nikis - 30-Nov-15 @ 3:47 PM
101 pound , 19 years old , female , in 75 degree house , died !
When will the jaw tighten up ?
Britt - 20-Nov-15 @ 7:54 PM
P.S to the last question,
Is necprophilia legal, and is it too soon after he has just died?
I'm the real batman - 15-Oct-15 @ 3:25 AM
I've tried burning my grandfathers body and I'm not sure it's working, he's still alive and keeps screaming? Can anyone help
batman is fake - 15-Oct-15 @ 3:23 AM
I have a question about my grandfather and how long his body can sit where it is ?? Can anyone help
Mandy - 14-Oct-15 @ 5:54 PM
How 2 know when will man dies?
Charu - 6-May-15 @ 4:26 AM
What is the boiling point of a human body to melt?
S.M.F - 29-Apr-15 @ 4:36 PM
@soos If to believe Ellery Queen's "The Dutch Shoe Mystery", rigor can set in a lot more quickly if the deceased suffered from diabetes. Not an expert, so a medic's comment would be welcome, but Queen has so far seemed to do his research carefully.
ellery queen - 3-Apr-15 @ 4:27 PM
@wickey - The decrease in body temperature drops two degrees celsius in the first hour, followed by one degree each hour thereafter.
ProfJ - 18-Mar-15 @ 12:19 PM
My mom died at the hospital around 12: 30 am, and her body was kept in the morgue. An autopsy was preformed around 12:00 pm. and autopsy report stated the her "body was still warm to the touch, which is consisted with a time of death of 1:48 am." I'm not a doctor but does the body remain warm almost 12 hours later. If someone could answer this question I will be internally grateful.
wickey - 15-Mar-15 @ 10:29 PM
@Kris - yes they do do autopsies on suicides....there may be different rules in different countries, but in the UK they do them.
Isaac - 6-Mar-15 @ 12:13 PM
1986 my friend best Christina died from a self inflicted gun shot to her head, she was 17, it was ruled a suicide. Her half sister and I have always felt like it may have been staged, but when she called the coroner to ask specifics about the autopsy they said that they did not do autopsies on suicide deaths, is that true?
Kris - 5-Mar-15 @ 10:17 AM
Question; 8month infant boy, 14 day sick with viral mengies[undiagnosed & untreated], fever +107deg, dies turns cold and blue, birth stats were 10.5 lb 23 in tall
death [guessed to be 10 lb or less 23 inch or more] due to ilness, indoors in a crib room temp 60+degrees [november 1973 slc,utah] id like to know how long i died.
Earl - 24-Feb-15 @ 9:05 PM
My brother's pupils (according to investigators photographs) were not dialated when he was found dead. It is estimated that he died one and a half hours earlier. I can't find any information as to why they wouldn't be dialated. Can anyone help me with this?
circle - 13-Feb-15 @ 9:56 PM
Given the body temperature vary only up to ambient temperature,then it means the equation is not of much help to determine the death time of a body which has already attained ambient temperature.For example if John was found dead in his bed at 7am,his body temperature 10degrees,which is equal to the room temperature then,determine his death time.This is complicated since we can't tell how long his body has been at this constant temperature equivalent to his room.
Derick.criminology student.chuka university
Dcio - 23-Dec-14 @ 8:58 AM
There's something I don't understand, after thirty hours the body will no longer be rigored and the muscles will get back to normal like living mucsles???
Swiftie - 6-Dec-14 @ 4:06 PM
i wanna askthat ,if someone like my naibhour called me for checking his mother or father for death confirmation , after chekin dody as per rule i declered death ,and some one suddenly ask ythat wat tha time of that .apart from tem, rigor process how can i know any spesipic clinical sign for time of death?
ahmed - 26-Nov-14 @ 8:54 PM
I'm a retired metropolitan police crime scene investigator, crime lab operator, expert witness, and retired university faculty where I taught forensic science.The questions here are very basic, but so many of them.I'll try to bounce a few quickly.
The time of death is important as evidence.It can establish or discredit statements of witnesses, victims and suspects.
You cannot enter full rigor in three hours.Opinions vary, but the Three Twelve's rule is a good guide; 12-hours to enter full rigor, 12-hours in full rigor, and 12-hours to exit full rigor.Small muscles are affected first, stay in rigor the shortest time, and relax fastest.Large muscles take longer to enter rigor, stay in rigor longer, and take the longest time to relax.Rigor establishes time of death; I always used jaw muscles v. buttocks or thigh muscles.A decedent with a stiff jaw but soft thigh muscles is in the first 12-hours.Both jaw and thigh in full rigor means the second 12-hour time frame, and soft jaw muscles and stiff thigh muscles means third 12-hour time frame.
You check the jaw muscles by wiggling the chin from side-to-side, and the larger muscles by simply pressing hard into the muscle with a straightened finger.
The first sign of death is livor mortis --- post-mortem lividity; a "bruising"on the underside of any body part that is facing down.It looks identical to trauma, and a person who died face down will look as if they were beaten to death.I've known cases where parents were wrongly arrested for a SIDS death because it appeared that the baby had been beaten to death.Lividity becomes pronounced in 2-4 hours.
Body temperature is of value only in deaths that have recently occurred.The body may cool, or the body may heat ---- it is 100% dependent upon the ambient temperature.If you die in the Arctic your body temperature will rapidly decrease.If you die at sea level on the equator where the air temperature is higher than the 98.6 F of the human body, you would not cool; your body temperature would rise.Generally, bodies cool since at death most people do not die in such upper extremes of temperature.The temperature method is most accurate for indoor bodies with thermostatically controlled constant air temperature, and no change in temperature over time has meaning unless the ambient temperature is factored it.Calculating time of death from core body temperature is more complicated than the simple equation because different ambient mediums have different transfer rates ---- water submersion results in radically more transfer of heat than air, while soil factors in-between.Surprisingly, clothing and adipose tissue (body fat) are not significant factors in heat exchange but it would take too long to explain.Basically, tissue and clothing ARE insulating factors which preserve body temperature, but only when body heat is there to offer the insulation a change to preserve the heat.When the body's heat-producing c
Eurastus - 5-Nov-14 @ 7:36 AM
'Additionally it is worth noting that a body's temperature will drop much more slowly if the body has been exposed to extreme cold"...
May I know, isn't thatbody's temperature will drop much more faster?