I have a question about rigor, we are working on a case and no forensic expert has been hired yet, so we are working with what we have. Here's where we get confused, the police are saying the man was shot (once chest/once chest) 40 cal. gun between 2:05 and 2:20. However, the maintenance man tried to roll over body and guy was stiff and he could not move his arms, the fingernails were already blue and lividity had set in, and this occurred at 2:29 - is this possible, autopsy does not state time of death. I am of the impression the murder happened earlier? Any thoughts?

The following is not for everyone and can upset some, only read if you really want to


Moment of Death:
1} The heart stops
2} The skin gets tight and grey in color
3} All the muscles relax
4} The bladder and bowels empty
.. . 4a - Men will get an erection. No, I don't know when, exactly. I really didn't feel like calling up the local mortuary and asking this. And there's people on my mailing list I could have asked, I bet, but it's kind of weird popping up and asking that. No pun intended. I'm not sure my parents know what erections are, so I can't ask them. I did read that this was one of the reasons hangings were so well attended by women, back in the old.days. Big Laffs, seeing the Hung, hung.
5} The body's temperature will typically drop 1.5 degrees F. per hour unless outside environment is a factor. The liver is the organ that stays warmest the longest, and this temperature is used to establish time of death if the body is found within that time frame.


After 30 minutes:
6} The skin gets purple and waxy
7} The lips, finger- and toe nails fade to a pale color or turn white as the blood leaves.
8} Blood pools at the lowest parts of the body leaving a dark purple-black stain called lividity
9} The hands and feet turn blue
10} The eyes start to sink into the skull
After 4 hours:
11} Rigor mortis starts to set in
12} The purpling of the skin and pooling of blood continue
13} Rigor Mortis begins to tighten the muscles for about another 24 hours, then will reverse and the body will return to a limp state.


After 12 hours:
14} The body is in full rigor mortis.
After 24 hours:
15} The body is now the temperature of the surrounding environment
16} In males, the semen dies
17} The head and neck are now a greenish-blue color
18} The greenish-blue color continues to spread to the rest of the body
19} There is the strong smell of rotting meat
20} The face of the person is essentially no longer recognizable


After 3 days:
21} The gases in the body tissues form large blisters on the skin
22} The whole body begins to bloat and swell grotesquely. This process is speeded up if victim is in a hot environment, or in water
23} Fluids leak from the mouth, nose, eyes, ears and rectum and urinary opening


After 3 weeks:
24} The skin, hair, and nails are so loose they can be easily pulled off the corpse
25} The skin cracks and bursts open in many places because of the pressure of Internal gases and the breakdown of the skin itself
26} Decomposition will continue until body is nothing but skeletal remains, which can take as little as a month in hot climates and two months in cold climates. The teeth are often the only thing left, years and centuries later, because tooth enamel is the strongest substance in the body. The jawbone is the densest, so that usually will also remain. So don't forget - brush regularly and floss only if you're really bored.

Hey, I'm new here and my opinion is not from experience or a professional opinion but I am a forensic science student/major.

In my opinion I would think that the time of death was before that. Rigor mortis takes longer than that to set in. I will update with more information when I get out of class and am able to post more detailed information strictly about rigor mortis.

Rigor is only one of many signs used to determine time of death, most likely according to this the death happened earlier but it could happen with some stiffing within about 30 minues. Also what other factors besides rigor could make arm movement harder that has not been determined. Internal body temp would have to also be taken and used as a quideline. And in the end without other evidence time of death is just an estimate depending on outside temp and other factors. Guessing at it within 1 or 2 hours is still good. And what if the person was already having breathing issues for some medical reason before being shot, he may have some blue coloring ad lividity setting in prior to death. For example many with congestitive heart failure will have these signs 2 or 3 days prior to death.

Rigor Mortis

The reason the body becomes rigid after death is the loss of adenosine triphosphate (ATP) from muscles. ATP is the compound that serves as energy for muscular activity. Without it muscles can’t contract. The presence and stability of ATP depends on a steady supply of oxygen and nutrients, which are lost when the heart stops. When ATP levels fall muscles contract and stiffen, producing the rigidity of rigor mortis. The later loss of rigidity and appearance of flaccidity of the muscles occur when the muscle tissue itself begins to decompose as part of the putrefaction process.

Rigor mortis begins throughout the body at the same time, but the muscles become rigid at different rates in predictable pattern. When conditions are normal (ambient temperature is about 70 F) rigor mortis sets in as follows:
-Beginning about 2 hours after death, rigor mortis is first detectable in the small muscles of the face and neck and progresses downward in a head to toe fashion to the larger muscles.
-The entire contracting process takes about 8 to 12 hours, after which the body is completely stiff and fixed in the position of death.
-The body remains fixed after another 18 hours, a state that is called the rigid stage of rigor mortis.
-The process reverses itself and rigidity is lost in the order in which it appeared, beginning with the small muscles and progressing to the larger ones.
-After another 12 hours or so, the muscles become relaxed in the flaccid stage of rigor mortis.

Under normal conditions, rigor mortis is useful only for estimating time of death during the first 36 to 48 hours to death.


Lividity is caused by stagnation of blood in the vessels. At death, the heart stops beating and blood ceases to move. Stagnant blood goes to location gravity takes it. Any body part that presses against a firm surface is pale and surrounded by lividity.

Red and pinkish discoloration reveals high levels of oxygen in the blood, which may be caused carbon monoxide or cyanide poisoning or by exposure to cold temperature after death. People dying from severe heart failure, shock, or asphyxia may develop deep purple lividity. The blood in these situations is usually poorly oxygenated and deep purple in color and equals lividity being deep purple.

Lividity typically appears within 30 minutes to a couple of hours and reaches its maximum by 8 to 12 hours after death. During the first 6 hours after death, rolling the body to a different position can shift the discoloration. When a body is supine (on its back) for a couple of hours and then rolled onto its left side, the lividity that began accumulating along the back shifts and begins accumulating along the left side. But after 6 to 8 hours, the lividity becomes fixed, because the blood vessels begin breaking down, and the blood settles in the surrounding tissues. Then, as the blood cells begin to break down, they permanently stain the tissues.

Cadaveric spasm, which often is confused with rigor mortis, is the instantaneous onset of stiffness throughout the body. A corpse that is affected by cadaveric spasm is locked in the exact posture it was in at the moment of death. Cadaveric spasm occurs under extremely violent physical and emotional circumstances.

My Dad died Aug 7th 2007 and had this... the corner stated to us that Dad died in his sleep and was gone 3-4 hours

I need answers today guys about all forensic definitions

Mechanism of rigor mortis?

Why do you think small muscles of the face show signs of rigor mortis?

Rigor mortis affects all muscle groups. Voluntary, involuntary, smooth and striated, large and small.

Here is a website that is non-technical and provides considerable information on Rigor including progression: Forensic Pathology

Hope that answers your question. If there is anything further just ask.

Hgsahgha