Medicolegal Death Investigations: Determining the Time of Death, Research Paper Example

Abstract

This paper explores how medicolegal death investigators, determine the time of death during an investigation. The paper examines this from a number of different perspectives including that of the legal / criminal justice, forensics and medical viewpoints.  The paper is divided into three parts: (1) provides an Introduction and background to the study (2) Provides the main analytical response and (3) Provides the summary conclusion and key points resulting from the analysis.

Literature Review

There is a considerable literature base on the subject matter of Medicolegal Death Investigations. This paper has refined that search to cover a number of key important papers.  In particular Chapters 6 and 7 of Forensic Science under Siege by Kelly M Pyrek.  This book considers the determination of death from the forensics viewpoint. (Pyrek,K.M. 2007).  A journal article produced by B. Brinkmann in the International Journal of Legal Medicine entitled – Harmonisation of Medico-Legal Autopsy Rules, (Brinkmann, B. 1999).  The paper considers the adequacy and accuracy of medical investigations conducted in different countries.  The latest works produced in 2011 by the authors James M. Adcock, Sarah L. Stein entitled – Cold Cases and evaluation model with follow-up strtategies for ionvestigators.  ( Adcock, J.M.2011).  Finally, the work of authors Jason Payne-James, Anthony Busuttil, William S. Smock who developed a book reviewing the different determination of deaths and causation entitled – Forensic Medicine: Clinical and pathological aspects. (Jason Payne-James, 2003).

Introduction

A medicolegal death investigator is a niche profession governed in the USA by American Board of Medicolegal Death Investigators (ABMDI).  The board seek to impose professional standards and procedures upon its members carrying out investigations within the context of criminal investigations, forensics and medical analysis. Certification came about with the co-operation of the National Institute for Justice in 1997. Members now gain professional certification in the subject matter.  (ABMDI, 2011).

Most of this type of work is conducted by forensic pathologists that work for the Police in the capacity of Criminal investigations of homicide.  The US Department of Justice has set out a comprehensive set of guidelines covering the procedural base of medicolegal death investigation entitled – Death Investigation | A guide for the scene investigator. (US Dept of Justice, 2011).   The legal definition for the time of death within the context of a homicide scene investigation is determined during the course of the forensic examination of the body. The fact that a body is found at the crime scene does not always mean a murder.  For example the person may have had a heart attack, died from a sudden medical illness like Cancer or maybe a suicide, death from a car accident or other illness. The examination therefore has to be precise.  There will be at least two determinations of time of death at the crime scene i.e. the police officers estimate of the time of death and the Medical Examiners Estimate.  The Medicolegal Examination should take place within 4 hours of death occurring. This can be a demanding requirement as the body start to cool down after death and after 30 hours increases due to decomposition setting in.

The forensic examination is a critical component of any criminal investigation where a corpse or body is concerned.  It is important that an accurate record of the time of death is determined together with the cause of the death.  This will be used as evidence in any subsequent trial and part of the coroner’s report. The person carrying out the forensic examination needs to be a highly qualified subject matter expert and is often an integral part of the criminal investigation team.

Determination of Time of Death

Legal Interpretations

The concept of ‘legal death’ is pronounced by a qualified person normally part of the forensic team and / or the Coroner.  The actual time of recorded death. Legal issues and qualified opinions may vary according to the type of death being recorded i.e. Murder Victim, Suicide, Accidental Death, Manslaughter, Medical Condition etc.  A qualified medical practitioner in the USA may examine a body and pronounce death, thereby issuing a valid death certificate.  The Coroner is more concerned with the conducting of autopsies to determine the cause of death, although time of death may also be a factor here.  In a criminal investigation the investigating team will use the death certificate, physical evidence of pronouncement of date and time of death by the medical examiner and the Coroner’s report providing more detailed forensic evidence and medical reports on the causation of death. Both may be exhibits in a subsequent criminal trial investigation.

Medical and Forensic Considerations

The symptoms of death may fall under a number of different broad categories. For example:-

Liver Mortis

Describes a settling of the blood and is normally located in the lower part of the abdomen.  This symptom of livor occurs very soon after death and is associated with the blood flow and cardiac arrest.  It generally takes on a dark blue or purple coloration but components in the blood stream may cause it to take on a different coloration. This inspection is therefore very useful in criminal or homicide investigations where poisoning may be suspected.  When carrying out this inspection time is of the essence. The observation is recognizable some 2-4 hours after the death occurring and within 8-12 hours of death it becomes fixed or complete.  Although the mark does not disappear it will change in coloration owing to the onset of body decomposition. (McFeeley, P.J. 2011)

Algor Mortis

This condition concerns the reduction of the body temperature following the time of death.  It shows or illustrates a steady decline until reaching an ambient temperature. The concept of Algor Mortis is an important part of any forensic investigation and helps in recording or estimating the time of death. The parameter of PMI estimation within the first 24 hours of death taking place. The degree of accuracy is best measured in cool or temperate climates as hotter climates reduce the loss of heat being eliminated from the body.  The bacterial infection within the body has even been seen to raise the temperatures when an autopsy is taking place. The normal rate of measurement is by a thermometer that measures the cooling rate of the brain, liver and rectum. (Lerner, B.W.  2011)

Rigor Mortis

The concept of rigor mortis or the stiffening of the body, due to the contraction of all muscles, normally occurs within about 3 hours plus after death.  In temperate climes this this condition lasts for around 36-48 hours and in tropical climates around 9-12 hours.  The interesting situation in forensic examinations  is that if a murderer moves the body after death and places it in a new position it will become frozen in that new position. Hence the original characteristics of the crime scene would be modified.  As such rigor mortis on its own cannot establish the precise position the body was in at the time of death.  This phase is also not helpful to the pathologist in the determination of the time of the cause of death. The concept of muscle dilation can produce misleading results. (McFeeley, 2011)

Pallor Mortis

This relates to a pale color that the patient takes on normally 15-20 minutes after the onset of death.  This is caused through the lack of capillary circulation and can be a useful barometer of the time of death for those early on a crime scene.  Little attention has really been paid to this but it is possible to use opto electronic colour measurement machines for examination of pallor mortis in early recorded deaths.  The hair on the skin is needed to be removed in order to prevent distortion of results.  Because of the rapidity of this action it has no real use in recording the time of death (Schafer, 2000)

Potassium Levels

This was a break-through in the ability to determine the precise time of death taking place. It was derived by the estimation of potassium levels in the cadaver vitreous humour.  This followed the pioneering research of Naumann who first observed the increase in vitreous potassium levels that occurred after death.  Early attempts failed to provide exact time recording for the time of death. Vitreous Humour changed this because it had a larger volume   and was free from contaminants. In addition because this was extracted from the eye, it was remarkable that in most instances of death the eye escaped injury.   The early experiments extracted samples from 99 eyes of 50 dead patients where the exact time of death was known in a hospital setting.  In each case two samples were obtained and the potassium levels were measured by use of a flame photometer. The scientists were then able to provide an exact mathematical formula that allowed the accurate recording of the time of death. This being a coefficient of correlation being calculated as follows:

X=X+bxy(Y-Y)—-(1)

X= The estimated time of death in hours

Y= Potassium values in meq/lit

Bxy= coefficient of regression (Agrawel, R.L. 1983)

Environmental Factors

Pathologists and other Forensic Scientists work in clean environmental laboratories.  It is important to have clean sterile conditions for this work.  This particularly when doing DNA analysis. A full service Crime Laboratory or Forensic Laboratory contains the following type of typical services; these being divided into two components i.e. Field Analysis and Laboratory Analysis. Field Analysis relates to the work of investigators that examine the crime scenes and collect forensic evidence. This usually contains a team of three people (i) Forensic Evidence Technician (ii) A crime scene investigator and (ii) A crime officer that examines the scene of the crime.  Laboratory Analysts are scientific personnel that examine the exhibits brought in from the field in order to conduct scientific tests such as blood splatter analysis, DNA tests or bullet striations etc.

Costs are often the main factor that limits the services in Forensic Laboratories. Timothy Pifer a NHSPFL Director in the USA was quoted as saying, we’re a relatively small state and as such have only one forensics laboratory to cover the entire state.  (Goudarzi.S, 2011)

Forensic Entomology

Forensic entomology provides for the use of insects, as appropriate to the decomposition of the remains of individuals. Essentially the study is broken down into three discrete areas i.e. (i) Medico legal (ii) Urban and (iii) stored product pests.  The insects have the potential to cause markings or wounds on the skin that may subsequently be misinterpreted as prior abuse of the victim. This type of forensic investigation has been useful in examination in the lack of care in the elderly within the private and institutional care system. Also cases of child abuse e.g. where wasp stings were used to punish children.  Insects also have the capability of corrupting blood spatter scenes, particularly roaches that my walk over the blood spatter and create a misleading blood trail. This is often undetected by the untrained eye. (Byrd, 2011)

The Forensic Laboratory

A full service Crime Laboratory or Forensic Laboratory contains the following type of typical services; these being divided into two components i.e. Field Analysis and Laboratory Analysis. Field Analysis relates to the work of investigators that examine the crime scenes and collect forensic evidence. This usually contains a team of three people (i) Forensic Evidence Technician (ii) A crime scene investigator and (ii) A crime officer that examines the scene of the crime.  Laboratory Analysts are scientific personnel that examine the exhibits brought in from the field in order to conduct scientific tests such as blood splatter analysis, DNA tests or bullet striations etc.

Small states like that of Maine, Vermont and New Hampshire are prime examples of where only one crime forensics laboratory exists.  One of the most important tests conducted in the Forensic Laboratory is that of DNA testing.  The reason this is so important is that because not only does it help in tracking the guilty party it can also set innocent parties free.  Eye Witness testimonies in the courts have been refuted by DNA analysis and released innocent people.  DNA retrieved from a crime scene is one of the most compelling forms of evidence in proving the person was at the scene of the crime.  Hair, skin and blood deposits all create a unique fingerprint in forms of identifying individuals.

In the early days the cross matching of finger prints was a long and time consuming process as this had to be accomplished manually looking at ridges and scales in the prints. The use of computers has now made this a much more expedient and robust process. (Oracle, 2011). Comparative analysis by computer is by scanning the print and then cross-matching by graphical images in a database.

An Australian Researcher  has found a way of using Amino Acids to detect old dry and used fingerprints that cannot be detected by traditional powder methods.  This is a breakthrough in Forensic Science. The new technique enhances old and degraded fingerprints and provides a much clearer image. The diagram below shows biometric matching and how two prints are plotted to achieve a match.  Location and points are plotted from one print to the other for multiple correlations or matches.

Historical Developments of Forensics

1950    It was August Valmar, Police Chief in California, established a school of criminology

Max Freisulzer a Swiss forensics expert developed ‘tape lifts method of collecting evidence

1951    F.H. Allen developed the ‘Kidd Blood Grouping’ system

1954    R.F. Bortenstein invented the breathalyser

1958    Weisner developed a test to prove O+ blood types

1975    Federal rules of evidence for US Supreme Court

1977    FBI introduced automated fingerprint system

1984    Sir Alex Jeffrey 1st DNA profiling test

A criminal defence attorney has an extremely tough time in securing a conviction where forensic evidence is shoddy and does not stand up to scrutiny in court.  The Houston City Police Department are described as having a poor track record in this area. In 2002 it went so far as the Forensic Lab in the city was even shut down.  This being primarily due to the mishandling of DNA analysis by Lab Technicians. They also had a history of losing fingerprint evidence or mishandling the evidence. The FBI and State Law enforcement agency rely heavily upon forensic evidence, this despite the fact that no protocols or standards legitimise the practice and use of these.

One embarrassing incident involved the FBI arresting an Oregon Lawyer for his believed involvement of the terrorist bombing in Madrid. He was arrested by the FBI in May 1994 and detained for 17 days based upon a match of a fingerprint from the crime scene.  The fingerprint being discovered on one of the detonating devices at the crime scene by the Spanish authorities.  It was later discovered that this was an error and the print belonged to an Algerian National. The FBI was forced to admit that it had made a terrible mistake and released Brandon Mayfield the Oregon Lawyer.  It was embarrassing because the FBI claimed absolute confidence that the print was a match. Despite the sophistication of computer imaging equipment and sophisticated matching software, there still remains scope for human error as was the case here.

Extracting Prints From Deceased People

This has always represented a significant challenge when rigor has set in and stiffened the fingers. The use of ink or black fingerprint powder has proved difficult in getting a clear and concise print.  Portable scanners have helped to alleviate the problem. Another method has been to sprinkle black fingerprint powder on scotch tape and lift the print off the deceased’s finger.  The print can then easily be

Conclusions

The Forensic Scientists however have many other analysis techniques at their disposal including blood splatter, fibre analysis, hair samples, DNA testing, chemical testing, glass and soil samples, etc.  It is often a combination of forensic evidence together with the sworn testimonies from witnesses that provides conclusive evidence on a particular crime scene.  Contamination of evidence has proved an issue and police officers need to take great care in the prevention of this before the forensic team have thoroughly inspected the crime scene and removed all types of forensic evidence.

The subsequent incorporation of DNA testing has considerably strengthened the packaging of forensic evidence.  One of the most important tests conducted in the Forensic Laboratory is that of DNA testing.  The reason this is so important is that because not only does it help in tracking the guilty party it can also set innocent parties free.  Eye Witness testimonies in the courts have been refuted by DNA analysis and released innocent people.  DNA retrieved from a crime scene is one of the most compelling forms of evidence in proving the person was at the scene of the crime.  Hair, skin and blood deposits all create a unique fingerprint in forms of identifying individual.

References

ABMDI. (2011, 10 18). ABMDI Certification. Retrieved from ABMDI: http://medschool.slu.edu/abmdi/index.php

Agrawel, R. G. (1983). Determination of the time of death by estimating potassium levels in the cadaver vitreous humour. Indian Journmal Opthalmol, 528-31.

Brinkmann, B. (1999). Harmonization of Medico-Legal Autopsy rules. International Journal of Legal Mediciine, 1-14.

Byrd, J. (2011, 10 24). What is Forensic Entomology? Retrieved from Forensic entemology: What is Forensic Entomology

Goudarzi.S. (2011, 10 19). Perspectives on a Forensic Lab. Retrieved from Lab Manager: http://labmanager.com/?articles.view/articleno/3425/article/perspective-on-a-forensic-lab 22/05/2011

James M. Adcock, S. L. (2011). Cold Cases: evaluation model with follow up strategies for investigators. Boca Ratton FL: CRC Press.

Jason Payne-James, A. B. (2003). Forensic Medicine: Clinical and Pathological aspects. San Francisco CA: GMM.

Lerner, K. L. (2011, 10 19). Time of Death. Retrieved from World of Forensic Science: http://www.enotes.com/forensic-science/time-death

McFeeley, P. (2011, 10 19). Liver Mortis. Retrieved from Federal Crominal Defence Investigation: http://federalcriminaldefenseinvestigator.blogspot.com/2009/05/livor-mortis.html

Pyrek, K. M. (2007). Forensic Science under Siege. San Diego CA: Elsevier.

Schafer, A. (2000). Color Measurements of Palor Mortis. International Journal of Legal Medicine, 81-83.

US Dept of Justice. (2011, 10 18). Death Investigation | A guide for the scene investigator. Washington DC: US Dept of Justice.