DNA to the rescue

How Genetech found the real perpetrator of Seya's rape and murder:

by Carol Aloysius

A wave of crimes against mainly children reached its peak with the rape and killing of five-year-old Seya Sadewmi, whose body was dumped in a canal close to her home at Kotakadeniyawa.

Seya would have celebrated her fifth birthday on - September 11-the day she was buried, her parents having even chosen the cake and frock she was to wear for the occasion. Her murder, although one in an increasing list of child rape and murders that have taken place this year, shocked and stunned the Lankan public.

As the manner in which the murder was supposedly committed ( based mostly on conjecture initially,) unfolded on television screens and in newspapers, there was a collective demand for justice and a quick sentencing of the perpetrator. In the weeks that followed, as conflicting theories on who was responsible for the heinous killing of a pre-schooler swirled, neighbours, friends and acquaintances of the deceased child's family added fuel to fire with their contradictory first hand knowledge, on how the crime had taken place and who was responsible for it.

Fingers pointed at first to a 17- year- old school boy and then at a father of one. In the case of the schoolboy, the Police found a photo of the little girl on his mobile phone. He was allegedly assaulted at the police station while being interrogated, the boy was found to be innocent of the murder. Then it was 32-year-old Dinesh Priyashantha alias 'Kondaya'. After admitting to having committed the crime giving the Police a gruesome description of how he had allegedly committed his horrific act and spent time in jail, Kondaya suddenly decided to retract.The real murder he charged was not he but his older brother Saman Jayalath.

New twist

In a new twist to this Who Dunnit mystery, it was reported just a few days ago that a petition was filed with the Sri Lanka Human Rights Commission (SLHRH) by the President of the Teachers Union Joseph Stalin , stating that the two reports compiled by the Judicial Medical Officer (JMO) during the investigations, contained contradictions and inconsistencies. He charged that the evidence had been 'doctored'in order to complete the case as soon as possible.

On Tuesday this week, the final report with regard to the murder was submitted to the Negombo Magistrate by Genetech Institute a leading pioneer in using DNA evidence to solve crimes and prevent crimes in Sri Lanka using a number of sophisticated tools to identify the perpetrators in its lab at Narahenpita, which incidentally received the ISO 15189 2007.

DNA testing

Senior Scientist and Head of the Molecular Forensics Dept. at Genetech, Dr. Ruwan Illeperuma, explained the procedure used and why DNA testing is hundred percent accurate when applied to identify perpetrators of crimes such as Seya's rape and murder.

Asked if he believed that DNA, an acronym for Deoxribonucleic Acid, an evidence in criminal investigation has grown in recent years and was now recognised as one of the most powerful tools in solving crimes in Sri Lanka, he answered in the affirmative. Why? " Because it contains all the genetic information about a person. It is in fact the instructions for the body's entire genetic make-up phonotypical and functional traits." How can it help to identify a particular person as the criminal? "Because it is unique to each individual person. Each person has the same DNA throughout his entire body and it is located in almost every cell but is different from every other individual." Describing what these cells were, he said, "Cells are the basic building blocks of all people."

Asked for his comments with regard to DNA testing, he said, "The first application of this technique for crime investigation in Sri Lanka was in 1999 by the renowned DNA scientist Dr. Maya Gunasekara who was also the founder of Genetech". " Since a person's DNA is located in every cell throughout his entire genetic make-up the body of an individual, any biological materials left detached from the body at the crime scene will contain DNA .

What we usually look at, I am referring to as biological material here are hair, blood drops, saliva, teeth, mucus, finger nails and semen. Other than that, we can also use physical objects as DNA evidence such as cigarettes butts, clothes, stamps, leftover food with bite marks and used cups and used chewing gum."

Precautions

Citing examples of precautions law enforcement officers take to prevent contamination of DNA evidence at a crime scene, he said they had to wear gloves and face masks, avoid coughing or sneezing on the DNA evidence, preventing samples being exposed to storage of DNA evidence in direct sunlight, excessive moisture or increased temperature and use paper bags or envelopes instead of plastic bags which retain moisture that may damage the evidence during long -term storage. Even if a sample is contaminated with erogenous DNA, that can readily be identified during a proper testing procedure". He further added "All Scene of Crime officers Officers (SOCO) in the Department of Police have been specially trained in identifying, handling and preserving biological samples to be used for DNA testing", he added.

Commenting on DNA testing used at the recent crime scene in the Seya murder case, he said they came up with the final conclusion only after the tests carried out on the two brothers, Kondaya and Saman Jayalath have conclusively proved that the DNA profile and DNA samples recovered from Saman Jayalath's blood sample and the DNA profile recovered from the deceased individual were found to be 100 percent identical. Our final report submitted to Court was a very comprehensive DNA report with ten pages having multiple additional conclusions we made other than identifying the real perpetrator.

Process

On the process followed, he said they first had to get the biological samples recovered from the scene of the crime and autopsy as DNA evidence and get them tested for the DNA. "Each biological sample submitted to us has been individually tested to obtain their unique DNA profile. Thereafter, we analyse all the data available to us at that time, comparing the profiles and identifying the DNA sources i.e. number of individuals who have left samples at the crime scene. We then report to the Court that we have obtained DNA profiles and ask the Court to submit to us possible suspects for the Comparison Process to establish the origin of each biological sample and to conclude the analysis.

Once the suspects are produced, the DNA is extracted from a few drops of blood obtained upon written consent from each suspect to obtain each DNA profile. These profiles will then be compared with the DNA profiles of each biological sample recovered from the scene and the autopsy already obtained. If we get a perfect match upon comparison, it concludes beyond doubt, the relevant suspect is the source of that particular biological sample."

By doing such comparisons he said the intention was to establish the source or identify the perpetrator. "However, if DNA profiling data is analysed in depth, an experienced Forensic geneticist can also reveal other additional facts such as close family relationships of a particular individual which might include maternal and paternal history of the individual and also other close family relationships like maternity, paternity and siblingships. This additional information which cannot be usually revealed through conventional evidence collected during an investigation are extremely valuable in understanding the chain of events that have happened during a crime incident", he added. Nor is this the end of a Who Dunnit crime that has roused all Lankans from their comfort zones.

According to informed sources, the exact testing procedure and decision made during the entire procedure of DNA testing for this particular case by Genetech , are likely to be revealed when the case is submitted to the High Court.