FBI Law Enforcement Bulletin: May, 1996.

Suspect Restraint and Sudden Death

By Donald T. Reay, M.D.

Dr. Reay is the chief medical examiner for King County, Seattle, Washington.

When hog-tied restraint is used to control violent suspects, officers can take precautions to prevent sudden deaths.

One law enforcement technique for controlling violent suspects is to place them in a hog-tied and prone position by binding their hands and feet together behind their back and placing them on their stomach. This physically incapacitating position, however, makes it difficult for subjects to breathe and can cause them to die.(1)

Because of the risks associated with hog-tied and prone restraint, officers must monitor subjects closely for signs of respiratory distress. This article describes how hog-tied restraint can cause death, what other factors might contribute to such a death, some steps that can be taken to prevent sudden deaths, and what evidence law enforcement officers can provide to assist medical examiners during death investigations.

Positional Asphyxia

When a hog-tied subject dies, forensic pathologists generally attribute the death in whole or in part to positional asphyxia resulting from respiratory compromise. Positional asphyxia occurs when the position of the body interferes with the person's ability to breathe. Breathing involves interaction of the chest wall, the diaphragm, and the muscles of the rib cage and abdomen. Interference with proper breathing produces an oxygen deficiency (known as hypoxia) in the blood,(2) which disturbs the body's chemistry and creates the conditions for a fatal rhythm disturbance in the heart.

Contributing Factors

An examination of reported positional asphyxia-related deaths revealed that several other readily observable factors can increase a subject's susceptibility to sudden death when officers place the subject in the hog-tied and prone position. These include obesity and psychosis, which covers both organic (i.e., paranoia, schizophrenia, etc.) and drug- or alcohol-induced psychotic behavior.

A large, bulbous abdomen (a beer belly) presents significant risks because it forces the contents of the abdomen upward within the abdominal cavity when the body is in a prone position. This puts pressure on the diaphragm, a critical muscle responsible for respiration, and restricts its movement. If the diaphragm cannot move properly, the person cannot breathe.

The second significant contributing factor is psychosis, often induced by drugs or alcohol. Drugs, such as methamphetamine, cocaine,(3) and LSD, create a state of delirium frequently accompanied by violent muscular activity. The mind-altering character of these drugs, combined with the added outbursts of violent and vigorous muscular activity, can cause individuals to lose their breath more quickly than expected. When the hog-tied position prevents recovery from such an oxygen deficit, cardiac rhythm disturbances can occur, resulting in death.(4)

Other pre-existing physical conditions also can contribute to sudden in-custody death. Any condition that impairs breathing under normal conditions will put a subject at a higher risk of respiratory failure when a situation escalates to the point that hog-tied restraint must be employed. Heart disease, asthma, emphysema, bronchitis, and chronic pulmonary disease fall into this category. Clearly, officers subduing a violent subject will not be able to pause in the midst of the action to inquire about the subject's medical history. It might be prudent, however, for correctional officials to be aware of inmates' medical records and be alert for potential problems when using hog-tied restraint.


Criminal justice professionals across the country have sought methods to ensure the safety of subjects restrained in the hog-tied and prone position. The simple fact of the matter is that even if officers take precautions, hog-tied and prone restraint is inherently risky. Therefore, instructors should stress awareness and vigilance when teaching officers the proper use of hog-tied restraint.

First, officers must be made aware of the inherent risks of using hog-tied restraint. They should learn how the adverse position affects a subject's breathing and how to recognize signs of respiratory distress. They also must be able to recognize the factors that contribute to positional asphyxia.

Whenever hog-tied restraint is employed, officers should determine whether subjects have used drugs or suffer from cardiac or respiratory diseases. Hog-tied subjects should not be left on their stomachs; rather, they should be rolled onto their side. During transport, officers should ensure that hog-tied subjects do not fall face-down in the back of the squad car.

Instructors must stress vigilance in monitoring the subject's condition. The process of hypoxia is insidious, and subjects might not exhibit any clear symptoms before they simply stop breathing. Generally, it takes several minutes for significant hypoxia to occur, but it can happen more quickly if the subject has been violently active and is already out of breath. If the subject experiences extreme difficulty breathing or stops breathing altogether, officers must take steps to resuscitate the subject and obtain medical care immediately.

At present, no satisfactory alternatives to hog-tied and prone restraint exist. Police administrators who wish to prevent deaths that occur during hog-tied restraint should not authorize use of the maneuver. Yet, experience shows that sometimes no other type of restraint will control a violent, aggressive subject. Until an alternative method of restraint is developed, officers must be aware of the risks, vigilantly monitor subjects' conditions, and take every precaution to avert fatalities.

Death Investigations

When a subject dies while in the hog-tied restraint position, the autopsy sometimes reveals the presence of significant natural disease, such as heart disease. For the examining pathologist, this creates a dilemma. Should the death be attributed solely to the natural disease? Was the disease aggravated by the adverse position of the body? Or did the positional restraint alone cause the subject to die?

Unfortunately, current postmortem technology alone cannot make such a determination. Hence, the examining pathologist must make a judgment call. The pathologist needs three things to make an assessment - an autopsy, a toxicological analysis of body fluids, and a detailed history of the events surrounding the subject's death.(5)

First, a careful and complete autopsy can reveal whether a catastrophic natural disease, such as a heart attack or stroke, caused the death. Similarly, toxicological analysis of body fluids for the presence of drugs and alcohol can provide important information. Yet, such medical information cannot provide the complete picture needed to determine the cause of death.

Police agencies can help by providing a detailed description of events that led to and occurred during the restraint maneuver. Such a report should contain explicit witness statements about the subject's behavior - especially noting any unusual physical respiratory signs, such as vocalizing, gurgling, gasping, and difficulty breathing - as well as comprehensive circumstantial information about the arrest, take-down, and restraint. The medical examiner can use this information to make a careful, thoughtful analysis of the events in the context of the autopsy and toxicological findings.


Determining the cause of death of subjects who had been placed in the hog-tied and prone position is one of the most difficult tasks in all of forensic medicine. Many factors can convene to cause respiratory failure when officers use this restraint maneuver. If death occurs, law enforcement agencies must provide medical examiners with a clear and complete description of preceding events, so that doctors can determine the cause of death accurately.

Awareness of the potential for subjects to die in the hog-tied and prone position is the first step toward stopping it from happening. Training in the use of hog-tied restraint, monitoring subjects, and recognizing the signs of respiratory distress can help officers prevent sudden deaths.


  1. D.T. Reay, C.L. Fligner, A.D. Stilwell, and J. Arnold, "Positional Asphyxia During Law Enforcement Transport," American Journal of Forensic Medical Pathology 13, 1992, 90-97.
  2. D.T. Reay, J.D. Howard, C.L. Fligner, and R.J. Ward, "Effects of Positional Restraint on Oxygen Saturation and Heart Rate Following Exercise," American Journal of Forensic Medical Pathology 9, 1988, 16-18.
  3. Recent pharmacological research has demonstrated that physical restraint sensitizes laboratory animals to the effects of cocaine. These findings indicate that stress can augment some of cocaine's effects and that any type of restraint, including but not limited to the prone and hog-tied position, during cocaine agitation can result in sudden death. See R.L. O'Halloran and L.V. Lewman, "Restraint Asphyxiation in Excited Delirium," American Journal of Forensic Medical Pathology 14, 1993, 289-295.
  4. C.M. Pudiak and M.A. Bozarth, "Cocaine Fatalities Increased by Restraint Stress," Pharmacology Letters 55, 1994, 379-382.
  5. J.L. Luke and D.T. Reay, "The Perils of Investigating and Certifying Deaths in Police Custody," American Journal of Forensic Medical Pathology 12, 1992, 98-100.


Caring for Subdued Subjects

To minimize the potential for in-custody injury or death, officers should:

  1. Get hog-tied subjects off their stomachs
  2. Determine whether subjects have used drugs or suffer from cardiac or respiratory diseases
  3. Monitor subjects carefully for breathing difficulties/loss of consciousness
  4. Be prepared to administer CPR
  5. Obtain medical assistance immediately
  6. Inform detention facility custodians of pre-existing medical conditions or respiratory difficulty.

Adapted from "Positional Asphyxia - Sudden Death," Bulletin of the National Law Enforcement Technology Center, National Institute of Justice, June 1995.

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