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Estimating The Time of Death

Author: Jack Claridge - Updated: 18 March 2015 | commentsComment
Time Of Death Body Temperature Deceased

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.

Methods Used

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.

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[Add a Comment]
@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?
S.C. - 3-Nov-14 @ 5:15 AM
My mom died july 3 of this year..the coroner said she had amassive heartattack between 5 and 6 am, three people seen her move her car at 8:30.all her lights were on and that's unususal she never had her lights on in daylight.Someone plz help me figure this out
angie - 31-Aug-14 @ 9:55 PM
at the time of death, the temperature of human body instantly increase or decrease????
meet - 28-Aug-14 @ 7:30 PM
My mother was a sudden death, she supposedly checked at 4am and was alive, on checking at 7am she was in full rigor. Is this quick onset of rigor common.
soos - 7-Aug-14 @ 5:38 PM
at what temperature man can die?
siri - 6-Aug-14 @ 12:28 PM
my question is that,why sudden arises the fathers of insects and than leads to die when weather incur cold or after raining .
Dawer - 17-Jul-14 @ 9:53 PM
How much time a doctor keep a distance between time of death 4 to 6 hours or 6 to 12 hours
sanju - 13-Jul-14 @ 6:43 PM
I'm a tad confused by this article. At one point it states that "The process [of rigor] normally begins roughly two hours after death and can last for anything from twenty to thirty hours" but then it says that "Rigor... occurs in the body during the first thirty-six to forty-eight hours." Am I misunderstanding something?
Jude - 17-Jun-14 @ 4:25 PM
My father passed away in hospital about 10 mind before I arrived yet he was stone cold when I kissed his forehead. Is it possible that he could have gotten cold so quickly?
tas - 31-May-14 @ 12:03 PM
A 50 years old white male surgeondied in November 1939 .The outdoor temperaturewas between 0-10 C degree . From a photo of 5 daysafter his death there was no sign of body decay .What is the possible cause of his death, Septicemia or mercury poison ?
song - 10-May-14 @ 8:52 PM
My husband died of a heroin overdose. I'd like to know if anyone can help me with the time of death. He was found at 12:20pm. His urine: 6-MAM was .473mg/L Morphine >2.000 mg/L Codiene .578 mg/L Blood: Methamphetamine of 1.9 mg/L Amphetamine of .06 mg/L Codeine of .032mg/L Morphine of .178 mg/L Basically I know he died of a heroin overdose but I'm wondering if he was unconscious for a period of time before he died (based on the 6-MAM level) and, if so, what was his apx time of death?
Kelly - 15-Apr-14 @ 5:13 AM
To yo! it help the police to solve the case
Ariel - 14-Apr-14 @ 2:36 AM
I would like some help in the nearest accuret time of mt husbands death has is dose'nt make sence has I hav no timeor what the cause of when or what my husband died,he was found in bed at around 8 0 clock in the morning he was very relaxed and had slighty blue lip's and wasn't a small man the ambulance people recon around 6 0 clock in the morning but I went up to see my husband at 130 in the afternoon which was 6 and a half hour's later,he was still warm with one cold arm so I rolled him over to me to cuddle him nothing was stiff 'he was still relaxed'i took a look at his pupils they were dialated very tiny so I kept looking at his pupils turn'd from tiny to really large after about 2 minutes at me looking at them which I thought was odd can anybody help me in to why they did that when I was told approxamatly 6 o clock in the morning when he passed away so that's eight and a half hour's later .I would be greatfull has I need some kind of answer has to when he died has I think he was in some kind of comba and wasn't work on to save his life.
bambi - 25-Feb-14 @ 1:03 PM
"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." Is this right?Seems to me the body's temperature would drop much faster!
Nox - 27-Jan-14 @ 2:10 PM
pinky. i think 3:50 the estimated time of death of a munk. try to convert it. is says that the normal temperature of our body is 37.5 and losses 1.5 per hour. try it
ricks - 18-Nov-13 @ 10:53 AM
allof these knowledges are so interesting. so greatful for everyone whomconcerned. please teach me the details what happened,where,when, why ......about the monk death that @pinky talked about . i really need to know about this case . please, anyone, please tell me. thank you
inter.pol.japan - 24-Aug-13 @ 2:13 PM
Here are a couple of facts for this topic= AIR TEMP-A body will cool faster on a cold winter night than on a warm summer night.BODY FAT-Fat tends to insulate the body, so the more fat a person has, the slower the body cools after death.CLOTHING-Clothing also insulate the body, so heavy clothing will slow the rate of cooling.WATER-A body in water cools mush faster than one in air. Therefore, it is difficult to use body temp to estimate the time of death for a victim found in the water.Hope these facts help some of y'all in the future if every needing this, your very welcome for theses fact I have shared with you.
skittles:D - 29-Apr-13 @ 2:35 AM
@ Lexie,the equation would be 37.5- 1.5x = final temperature. but a simpler way would be totake 37.5- final temperatureand divide by 1.5. this will give you the number of hours that have passed. subtract them from the time the body was find and that's it. example. body found at 6 pm. temperature is 34.3.so 37.5-34.3=3.2 then 3.2/1.5 =2.13. which means 2.13hours have passed. take 2.13 away from 6 pm and you get 3.47 pm. so you can assume that TOD was around 3 47 pm
motus - 13-Apr-13 @ 3:51 AM
@ kat. the estimated time of death would be around 12 pm.
motus - 13-Apr-13 @ 3:33 AM
Hi, I am a high school student, and I am competing in a competition about forensic medicine, and all I need to know is the time of Death equation, I see that you have it above, by I do not understand it. If you would please explain it a little more in depth for me please? Thank you!!! :D
Lexie - 6-Mar-13 @ 2:53 AM
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