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Improving criminal investigation in Sri Lanka
DNA for justice
By Prof. S.K. Ballal and Suneth Sooriyapathirana
Sri Lanka's increasing crime rate has deeply upset the peaceful lifestyle and economic development of the country. The Department of Police and national system of justice are heavily burdened and it is often debatable, whether the current investigating methods are effective in meeting the backlog of cases.

DNA profiling and DNA databases are commonly employed for criminal investigations in developed countries. This is an improvement on the traditional system of criminal investigations, especially in terms of accuracy in decision making. It is suggested that this modern method be used in Sri Lanka as well.

The usual approach to investigation in criminal cases in Sri Lanka is through eyewitnesses and conventional forensic investigations. The most unfortunate mistake in a prosecution is imposing the death penalty or long incarceration on an innocent person.The most common cause of wrongful conviction is a mistaken testimony of an eyewitness. Evidence of an eyewitness is "persuasive" evidence in trials today.But memory is extremely plastic and unreliable even when the victim attempts to carefully "remember" the faces and events. Time lapse, stress, confusion and fear can lead to a false identification.

The conventional approach of forensic investigation is another channel of finding evidence. It includes post-mortems and biological evidence. Most often in bomb blasts, bodies are reduced to small particles and cannot be identified by conventional means.

What is DNA ?
Modern forensic DNA profiling is rapidly changing all facets of the criminal justice system because of the extreme sensitivity and high levels of accuracy inherent in this method. Therefore, it is necessary to understand the biological basis behind DNA profiling and why it has been considered as the most accurate system of identifying criminals in modern day police investigations.

Each of us is made up of hundreds of billions of cells and every individual is derived from a single fertilized egg cell. Fertilization is the union of male sperm (from the father) and female ovum (from the mother). Our cells have an enormous amount of complexity in structural arrangement with many parts inside. In the nucleus of the cells, threadlike structures called chromosomes are found which carry the genetic information called DNA that are essential for architecture, maintenance and reproduction of our bodies.

The DNA codes for genetic information define who we are and what makes us individuals with unique traits.
Each one of us is different in hundreds of characters while sharing many common features. This individuality exists because, each one of us has a unique set of DNA except for identical twins.

Wonders of DNA
All we need for investigation is a few cells of DNA .They can be extracted from anything ranging from a spot of blood , semen, hair, finger nail scrapings, to cigarette butts, and chewing gums. Biological samples that are decades old, ravaged by fire and decayed also can be used because DNA is relatively stable to drying, heat and degradation.

The first use of DNA profiling in a criminal investigation occurred in 1986 in the United Kingdom and in same year, the US Federal Bureau of Investigation (FBI) and the US commercial laboratories began using DNA profiling methods. In Sri Lanka DNA profiling was used to identify the suspects of the Hokandara mass murder and this technique is popularized in Sri Lanka as DNA fingerprinting although there is no "finger print" in a conventional sense.Now, it has been clearly defined with the correct term, DNA profiling.

Identification of the victims from the September 11, 2001, terrorist attacks on the World Trade Center, New York has been the largest and most difficult forensic DNA investigation in history because, in most bodies of victims, tissue destruction was total.

DNA profiles obtained from these human debris were compared with the DNA profiles that were obtained from the personal items from the victims’ houses - such as razor blades, combs, tooth brushes, clothing and other items as well as about 7,000 check swabs from the victims' relatives. By September 2002, about half of the World Trade Center victims had been identified.

The goal was the identification of all the victims by the middle of 2003, which has been accomplished. In July 1995, Serbian troops seized the Bosnian town of Srebrenica. About 25,000 Muslim inhabitants were attacked and over 7,500 people were shipped to execution sites, killed and buried in mass graves. This massacre was the largest mass murder since World War II. When DNA profiling was used, most of the victims were identified by the end of 2002.

There were similar incidents of mass graves in Sri Lanka at Sooriyakanda and at Chemmini in Jaffna Thus, DNA profiling could be used to probe these types of massacres.

Uses of DNA profiling
1. Convicting the guilty and exonerating the innocent-
DNA profiles from rape, burglary and other crime scenes can be matched with the suspects. Also, DNA profiles from multiple crime scenes can be compared in order to identify common perpetrators. Innocents could be exonerated. For example, in the US 123 innocent people have had their convictions overturned using DNA evidence alone. Twelve of these were death row inmates, some only days or hours away from execution. Cases already filed and convicts already punished can be re-examined if there is a suspicion that they were wrongfully convicted.

2. Excluding suspects -
History shows that in sexual assault cases, DNA evidence excluded about 25% of primary suspects prior to trial. This not only allows police forces to redirect investigations at an early stage but also saves resources and the injustice of bringing innocent people to trial.

3. Identifying missing persons -
DNA profiles obtained from the remains of missing persons can be compared with profiles from relatives in order to establish the identity of body or skeletal remains.

4. Establishing paternity -
DNA evidence can help to establish parentage. A recent example of DNA profiling in a paternity case was that of Thomas Jefferson, the third president of the US. The DNA profiling revealed that Jefferson could have fathered children by Sally Hemings, one of his slaves.

5. Identifying military personnel -
The military can obtain DNA samples from its personnel so as to identify soldiers who may be killed in the line of duty.

6. Identifying disaster victims -
DNA profiling can be employed to identify victims of air crashes, terrorist attacks and other catastrophes.

7. Identifying victims of mass murders and assassinations -
8. Identifying protected species (wild life forensics) -
DNA in animals
DNA samples have been used to determine whether the remains of a particular animal came from an endangered or protected species. DNA profiles have linked animal remains with a crime scene or with a suspect.

The reliability of DNA profiling can be significantly affected by the methods used to collect, store and analyse the crime samples, as well as by the interpretation of a profile. Therefore, authorities must recommend forensic laboratories be accredited for DNA testing so as to standardize methods and quality.

It is important to remember that the relevance of DNA profiling must be assessed in the context of evidence in a case, since a match between crime scene DNA profile and a suspect profile does not necessarily prove guilt in the absence of other evidence. Human error or contamination may contribute to a match between a profile from a crime scene sample and a profile from an innocent person.

In addition, a suspect's DNA may be introduced to a crime scene before, during or after the crime for reasons unrelated to the suspect's involvement in the crime. Also, DNA may be introduced to crime scene by inadvertent or deliberate tampering.

Human errors
Conversely, DNA profile exclusion does not necessarily mean innocence. In a rape case, for example, a suspect may not contribute to the semen sample, but may have been involved in the crime by restraining the victim.
Once again, DNA profiles must always be interpreted in the context of all available evidences.

Suspect-free and victimless cases are a serious problem for the Department of Police in Sri Lanka. One of the solutions that we are suggesting is the establishment of national forensic DNA databases like in many European and certain Asian countries like China.

DNA profile databases are rapidly proving to be valuable aids in criminal investigation although there could be certain legal and ethical questions in collecting and storing DNA profiles in databases. Everyone arrested for any offence that carries a prison term must be obliged to provide a DNA sample.

These samples are the profiles generated from them and can be retained by the police and entered in a National DNA Data Bank of Sri Lanka.
A DNA profile database can be established for all military and police workers as a start and samples be collected at the time of their recruitment. This will facilitate the issuing of death certificates soon after a violent incident.

Towards a matured justice system
DNA profiling and establishing databases for all citizens would be the ideal and fairer policy than profiling only certain individuals, but the cost factor, ethical and legal barriers might arise.

However, strong leaders must assure the citizenry that these databases will be used only for criminal investigations and the rights of all citizens will be honoured. Over the next decade, it will be increasingly important for all of us to understand the workings of these technologies and we believe that Sri Lanka can be in the forefront of small nations in leading the way.

In order to protect society and individuals from potential abuses, Sri Lankans should request their government to pay attention towards using DNA based evidences.

Scientists and technicians must be given proper training prior to their recruitment. Indirectly, this will open up a new avenue of employment in Sri Lanka. Police, lawyers, judges and the public must be informed of the potential and pitfalls of forensic DNA profiling so as to evaluate it and question it intelligently.

In addition, sufficient funding must be allocated by the government to ensure that all suspects have full and impartial access to this powerful new technology and that everyone is constitutionally protected.

(Prof. S.K. Ballal is Senior Professor, Department of Biology, Tennessee Technological University, Tennessee, USA and. Suneth Sooriyapathirana is a Lecturerin the Department of Molecular Biology and Biotechnology, University of Peradeniya)

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