(No article came in March and April due to payment dispute)

A similar article appeared at #66 (nov 1998)

For FEBRUARY 2001 issue

SCIENCE IN CRIME DETECTION

WHEN DID THE PERSON DIE?

-Dr. Anil Aggrawal

One of the most common problems to be solved by a forensic expert is the estimation of time since death. The police is frequently interested in knowing when the person died? If the forensic pathologist can tell the time of death with reasonable certainly, the task of the police becomes that much easier.

The situation becomes somewhat trickier, when the person has died within hours, and the forensic pathologist may have to pinpoint the time of death within a matter of minutes. Take the following example, which I am citing from a real incident.

A pregnant lady was taken to a hospital for delivery. Let us say the time the patient was brought in was about 10:30 pm. The hospital belonged to a quack, without a proper MBBS degree. But posing as a real doctor, he admitted the patient and started preparations for delivery. After the delivery some problem develops and the doctor loses nerve. He has no arrangement of blood in his hospital, and makes the relatives run to various hospitals to get fresh blood. The blood is brought, but by that time the patient is already dead. Let us say that this time is 2:00 am.

The relatives are furious. But the doctor asserts that the patient has not died. He tells them to take the “patient” to some other hospital. The relatives rush to the other hospital where the doctors declare the patient dead. The time is 3.00 am.

The relatives of the patient are furious. They sue the doctor for negligence. But the doctor has a very good defense up his sleeve. He can very well say that the patient was alive when he discharged the patient, and the patient actually died at the second hospital. If he can successfully prove this, no charge of negligence can be brought against him. Certainly it would be very difficult to prosecute him.

Since the relatives are not doctors, they can not be certain if their patient was already dead when they came out of the first hospital. All they can say is that the patient was not moving about, or making any movements. But that happens if the patient is unconscious.

Now the question that naturally arises here is, “When did the patient actually die”? If a forensic pathologist could say, that the patient died at, say, 1.30 am, then clearly the first doctor is at fault, but if the forensic pathologist could say that the patient died at, say, 2.45 am, it means that the patient was indeed alive at the first hospital and died only during the transit.

Many methods are available to the forensic pathologist to tell the time of death. But in early post-mortem intervals, i.e. when the dead body is seen by the pathologist within about 4 hours of death, the pathologist has a very strong tool in his hand, and this time we are going to discuss this relatively new technique.

Before starting further, we would have to be conversant with an interesting concept called “molecular death”. When a doctor pronounces a person dead, all his body cells (the average human body contains about 60 trillion cells!) are not dead. Only the most vital cells of his body, i.e. those of his brain are dead. Rest may still be alive. But since the brain cells are dead, the person “as a whole” can not be brought back to life, and the doctor pronounces him dead. When the doctor pronounces a person dead, it is called “somatic death”. In other words “somatic death” means that the person as a whole has died, while his individual cells may still be alive. Molecular death is a stage when ALL cells of the person die. This death occurs about 3-4 hours after the somatic death.

Now let us introduce another new concept – that of “tendon reflexes”. Let us not worry about the complicated sounding term. The basics are very simple. If a muscle of the body is struck lightly with a hammer, the muscle usually contracts. It is a kind of reflex action, known as a tendon reflex. The best tendon reflex is seen in the case of knee. If you strike the knee of a person with a hammer, his lower leg would suddenly give a jerk. This is known in common parlance as “knee jerk”.

A similar kind of jerk is seen in the upper arm. If the biceps muscle is stimulated by striking a hammer over it, it would also contract. Now it is very natural for everyone to assume that such jerks are seen only in a living person. But this is not true. In a recently dead individual, especially in one, in whom molecular death has not occurred, one can still see these jerks. The figures 001_a.jpg till 001_c.jpg, show only this phenomena. This is the arm of a dead person, which is showing contraction just as if the person was alive. This phenomena is seen upto about 4 hours after death. In the figure 001_c.jpg, the forensic pathologist has removed the skin around the biceps muscle and has struck the muscle directly. This is supposed to give better results.

Next series of figures is still more remarkable. The person in these figures are being given electric currents in their faces (around their eyes and mouth). From the grimacing pattern that is seen, you would quite probably say that this person is still alive. But actually this person is DEAD! Figure 002_a_001.jpg shows the post-mortem response of the facial muscles to electric current, 45 minutes after death. Note the "spreading" of the reaction. Figures 002_b_001.jpg and 002_b_002.jpg show the reaction 75 Minutes after death. Figures 002_c_001.jpg and 002_c_002.jpg show the reaction 105 Minutes after death, figures 002_d_001.jpg and 002_d_002.jpg show the reaction 135 Minutes after death and finally figures 002_e_001.jpg and 002_e_002.jpg show the reaction 165 Minutes after death. We see, that as the time passes the strength of the grimacing decreases. From these reactions the doctor can easily find out when did a person die, within a matter of minutes!

And finally one more thing. Look at figures 003_a.jpg till 003_c.jpg. Here the forensic pathologist is introducing a drug called homatropine in the recently dead patient. In an alive patient, this drug should dilate the pupils, i.e. the pupils should become much wider in diameter. Here in the dead individual, to get a quicker reaction the drug is being introduced inside the eye (technically speaking in an area called “anterior chamber of the eye”), and you can see that the pupils are still dilating. This is seen within about 4 hours. Thus we can safely tell the police that the person died within about 4 hours. If they do not dilate, the death must have occurred earlier than this. Another drug pilocarpine may be used in which case the pupils should contract.

This is thus a gist of what can be done to measure the early postmortem interval. In advanced centers abroad like in Germany this method is sometimes used in complicated cases to tell the time of death, if the death has occurred within about 4 hours. In our country too, this method can be used in complicated cases with good results.

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(Dr. Anil Aggrawal is a professor of Forensic Medicine at the Maulana Azad Medical College, New Delhi-110002. His E-mail is dr_anil@hotmail.com and his Website address is: http://members.tripod.com/~Prof_Anil_Aggrawal/index.html

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Note to the Editor: Please make all correspondence at S-299 Greater Kailash-1, New Delhi-110048. Phones (R): 6465460, 6291942, 6413101; (O) 3239271-4

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