It is often observed that on finding a ligature mark on the neck of a person, the investigating agency would be quick to carry out investigation prima facie treating the case to be of either homicide or suicide, unmindful of the fact that it could very well also be a case of natural death whereafter a scene of crime might have been meticulously created to simulate suicidal hanging...
It is often observed that on finding a ligature mark on the neck of a person, the investigating agency would be quick to carry out investigation prima facie treating the case to be of either homicide or suicide, unmindful of the fact that it could very well also be a case of natural death whereafter a scene of crime might have been meticulously created to simulate suicidal hanging or homicide to falsely implicate other persons due to personal/political rivalry.
In fact, it has been observed that postmortem examination primarily concludes the case to be one of suicide or homicide on the basis of position of ligature mark, cyanosis[1], petechiae[2] and congestion of visceras.
As a general rule, in ligature strangulation/suicide, the mark of ligature is positioned approximately horizontally, in contrast to hanging in most cases the mark slopes up to the point of suspension, situated high-up the neck, directed obliquely upwards the line of mandible[3] on both sides of the neck to pass behind the angle of jaw and mastoid process[4] and ending on the back of the scalp, leaving a gap in between the two ends of the ligature mark. In homicidal strangulation/murder, it may either totally encircle the neck or be seen only at the front. The latter situation arises when the ligature is pulled tightly from behind. In such cases, the mark may also be sloping if the ligature is pulled upwards from behind.
It is on the basis of above positioning of ante-mortem[5] ligature mark that a conclusion is drawn as regards homicide or suicide, although, such a ligature mark can be created post-mortem[6] as well. Normally the ligature mark will show signs of vital reaction[7] in ante-mortem hanging, however, Casper in his famous experiment, had very beautifully shown that even after death, if a dead body is made to hang, an hour or two after death, a typical ligature mark of antemortem hanging with its usual characteristics may be produced. The similar mark can also be produced by dragging or pulling the body after putting a ligature around the neck soon after and even at times one to two hours after death. Hence, the ligature mark alone is not conclusive of antemortem hanging[8] since such mark can be created post-mortem as well, which would simulate as ante-mortem.
The reason is that death in the clinical sense occurs primarily due to failure of functions of any one of the three main organs of the body i.e. heart, lungs and brain, leading to the extinction of life with cessation of respiration and circulation associated with complete stoppage of the brain function. To delve further into this, death, in fact, occurs in two stages i.e. somatic and molecular. Somatic Death or Clinical death signifies the death of a personality or death of the individual as a whole, when there is a complete loss of body functions, as stated above. However, Molecular death or Cellular death, on the other hand, signifies death of the tissues and cells of the body individually and does not occur before two to three hours after somatic death, since molecular life persists for variable period after occurrence of somatic death[9]. Therefore, though a person may be medically declared dead, however, his organs can function for a few hours even after the death and any injury caused during such period after death, though, is post-mortem but would have vital reactions simulating ante-mortem injury. As a consequence thereof, any ligature mark inflicted after the death may appear to be inflicted prior to the death.
The next sign of ante-mortem hanging is congestion of visceras (internal organs), which is a non-specific sign seen in many types of death and cannot be regarded as a reliable sign of mechanical asphyxia[10]. Normally when the neck is compressed, the face, skin, lips and tongue become swollen and reddened. Internal organs also become congested as a result of obstructed venous return. Oxygen is carried to various organs of the body by blood. Due to mechanical asphyxia by constriction of neck, the airway becomes blocked leading to impaired oxygenation in the lungs. This results in diminution in the oxygen content in arterial blood which would lead to darkening of all organs and tissues. Thus, the normal pink colour of well oxygenated skin may change to purple or blue when oxygen is lacking. However, bluish discoloration of skin or nails may appear in many hypoxic[11] conditions such as acute respiratory disease, syndrome, heart failure, etc., when oxygen carrying capacity is less than 6.7 ml/100 ml and cannot be restricted only in case of mechanical asphyxia. As such, cyanosis detected at autopsy is misleading and of no use as a diagnostic criteria of asphyxia. The bluish colour of the skin and nails referred to as cyanosis has to be interpreted with a great degree of caution in cases of mechanical asphyxia. Shapiro (1975b) has emphasized the misuse of term and regards it as a “non-committal chromatic appearance which is unjustifiable to invest diagnostic significance”[12]. Further, cyanosis produced during life may be partly or wholly overshadowed by hypostasis[13], which may be a deep purple or blue and may be mistaken for true cyanosis and for this reason, some pathologists refuse to use ‘cyanosis’ in respect of the dead, claiming that it cannot reflect the ante-mortem situation.[14]
The next sign considered by postmortem experts as conclusion of asphyxia is Petechial Hemorrhages or Tardiu’s spots, which occurs as a result of blood escaping from the capillaries due to asphyxial death typically seen in the eyes, face, neck, mucous membrane of the mouth and the viscera. However, the same is not conclusive and there have been reservations of many authors including Shaprio (1975A) on the validity of such hemorrhages that they are such a common finding in so many kinds of different deaths that any interpretation of significance is open to question. They are usually more pronounced in cases where there has been a degree of postural asphyxia, such as alcohol intoxication or status epilepticus[15]. They can also appear after death (Gordon & Mansfield, 1955: Hunt, 1958). The doubtful significance of petechia in mechanical asphyxia has also been emphasized in a study by Zaini & Knight (1982).
All the above so-called classic signs of asphyxia as a result of ante-mortem strangulation/hanging are thus, not conclusive and the investigators as well as the autopsy surgeons have to be mindful of the fact that besides medical evidence, there have to be other circumstances which distinctly point towards homicide or suicide and the possibility of an attempt to create a false scene of crime has to necessarily be ruled out.
The author is a Special Public Prosecutor for CBI as well as Special Counsel for Directorate of Enforcement at High Court of Delhi and a Defence Counsel in Criminal Matters. Views are personal.
[1] Bluish colouration of nails & skin.
[2] Haemorrhagic spots.
[3] Jaw bone.
[4] A pyramidal bony projection on the temporal bone at the posterior base of the skull i.e. bony projection behind the ear.
[5] Before death.
[6] After death.
[7] The response of living organism to a trauma which would not appear when the traumatic agent exerts its action after death like after infliction of a wound a series of vital reactions like haemorrhage, inflammatory self-infiltration takes place, which is the proof of ante-mortem injury i.e. the trauma had occurred during the life of the person and on that basis the trauma is declared to be ante-mortem. Such vital reactions would be absent in post-mortem trauma.
[8] Page no. 591 of Forensic Medicine & Toxicology- Volume-I by J.B. Mukherjee.
[9] Page no. 170 of Forensic Medicine & Toxicology- Volume-I by J.B. Mukherjee.
[10] Page no. 49 of Pathology of neck injury by Peter Vanazis.
[11] Hypoxia is a stage in which oxygen is not available in sufficient amounts at the tissue level to maintain adequate homeostasis i.e. a state of balance amongst all the body systems needed for the body to survive & function correctly.
[12] Page no. 49 of Pathology of neck injury by Peter Vanazis
[13] Hypostasis/post-mortem staining/post-mortem lividity: After death due to stoppage of heart circulation of blood ceases and the accumulated blood due to gravitation accumulates in the toneless vessels and dependent parts depending upon the respective position of body, thus imparting a deeper colour to the dependent parts.
[14] Page no. 324 of Forensic Pathology by Bernard Knight.
[15] Page no. 47 of Pathology of neck injury by Peter Vanazis