DNA testing has its limits
- Published: 1/10/2012 at 11:09 AM
- Online news:
DNA testing, often a difficult process, can help identify who was the victim was in a murder cause, but other evidence is needed to convict the murderer as is becoming clear in the case where a police doctor is the main suspect.
Pol Lt Gen Jaramporn Suramanee explains the procedures used in testing for DNA in bone samples that have been buried for a long time. WASSAYOS NGAMKHAM
Testing times in skeletons case
Identifying three corpses dug up at Phetchaburi site a painstaking task
Pol Lt Gen Jaramporn Suramanee. WASSAYOS NGAMKHAM
While murder suspect Supat Laohawattana has been arrested in connection with the disappearance of a couple in Phetchaburi, the case remains shrouded in mystery.
Police investigators are gathering forensic evidence to establish the identity of three skeletons dug up from the suspect's pineapple orchard in Phetchaburi. They're also putting pieces of evidence together to see if their deaths were connected to him.
The three skeletons were the very first pieces of evidence for police to work on in determining if Samart Noomjui and Orasa Kerdsap, the husband and wife who went missing about three years ago, were dead or not.
The best method of determining whether the skeletons were the missing couple or not was to conduct a DNA test.
The test results could be used to compare with DNA traces of the missing couple's relatives, said Pol Lt Gen Jaramporn Suramanee, assistant commissioner general of Thai Royal Police Office.
DNA tests of bone samples are usually performed within 24 hours of a body being found so the body tissues and fluids can still be used.
However, this was not an option in this latest crime investigation.
"The 12th rib is the best sample of all when it comes to extracting the DNA traces from bones because it is a soft bone, like an ear bone," Pol Lt Gen Jaramporn said.
Leg and arm bones can also be used for the test, he said. But if the skeletons have been buried for a long time, thigh bones were the next best thing, he said.
This particular part of bone is crushed and infused with liquid nitrogen which helps separate the DNA traces.
The whole process of preparing bone samples to analyse DNA results take a long time to finish, he said.
Obtaining DNA test results, however, is only the first step of the investigation.
Even if it is proved the skeletons were those of the missing couple, it must be established how or if Pol Col Supat was linked to the case.
Witness accounts and other pieces of evidence such as a weapon would have to be examined and compiled into the investigation file.
"As we all know, no murder charges have been pressed against the suspect so far. Only theft and illegal detention charges have been laid against him," Pol Lt Gen Jaramporn said.
These initial charges were brought against Pol Col Supat because the pickup truck owned by the couple was found recently at a house belonging to his relative in Nonthaburi.
Some eyewitnesses told police they saw him taking the couple away in a car before they were reported missing, Pol Lt Gen Jaramporn said.
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procedure – a way of doing something ขั้นตอนการดำเนินการ
sample – a small amount of a substance that is used for scientific or medical tests ตัวอย่างทดลอง
buried – covered completely by something, in this case, soil ฝัง
skeleton – the structure of bones that supports the body of a person or an animal โครงกระดูก
identify – to recognise who someone is ระบุชื่อ
corpse – a dead body ศพ
painstaking – needing a lot of care, effort and attention to detail อุตสาหะ, เพียรพยายาม, ระมัดระวัง
task – something that you have to do หน้าที่; ภารกิจ
suspect – a person who is thought to have committed a crime ผู้ต้องสงสัย
arrest – (of the police) to take someone to a police station because they are believed to have committed a crime จับกุม
disappearence – not able to be seen or found; การหายไป, การสูญหาย
couple – two people who are married or are involved in a romantic relationship คู่แต่งงานกัน, คุ่รัก
shroud – to hide something by covering or surrounding it ซ่อน, คลุม
mystery – not explained or known สิ่งที่ไม่สามารถอธิบายได้, ความแปลกประหลาด, ลึกลับ
investigator – someone whose job is to officially find out the facts about something, especially a crime or accident ตำรวจฝ่ายสอบสวนคดีอาชญากรรม
forensic – relating to the use of scientific methods to solve crimes or to find out why something happened เกี่ยวกับนิติวิทยาศาสตร์
evidence – facts statements or objects that help to prove whether or not someone has committed a crime หลักฐาน
establish – to determine; to discover something by examining evidence to or calculate something กำหนด, ระบุ, แสดงผล
orchard – an area of land where fruit trees are grown สวนหรือแปลงผลไม้
determine – to discover something by examining evidence to or calculate something กำหนด, ระบุ, แสดงผล
conduct – to do something in an organised way; to carry out — ลงมือทำ, ดำเนิน, ปฏิบัติ
trace – a very small amount of a substance จำนวนเล็กๆ
relative – a member of your family ญาติพี่น้อง
perform – to conduct, to carry out — ลงมือทำ, ดำเนิน, ปฏิบัติ
tissue – the substance that animal and plant cells are made of เนื้อเยื้อ
fluid – a liquid; a substance that can flow ของเหลว, ของไหล
option – a choice; something that you can choose in a particular situation ทางเลือก
rib – one of the long curved bones that are in your chest กระดูกซี่โครง
thigh – the top part of your leg, above your knee ต้นขา
crush – to press something so hard that it breaks into very small pieces กด บีบอัด
infuse – to slowly put a drug or other substance into something แช่, ใส่, เทใส่
separate – to keep or put apart แยก
process – a series of actions that you take in order to achieve a result แนวทางปฏิบัติ, กระบวน, วิธีการ
analyse – to examine the nature or structure of something, especially by separating it into its parts, in order to understand or explain it วิเคราะห์, ศึกษา, ตรวจสอบ
obtain – to get something that you want or need, especially by going through a process that is difficult ได้มา, ได้รับ
link – a connection การเชื่อมต่อ
witness – a person who sees something happen or knows about something ผู้ที่เห็นเหตุการณ์, พยาน
account – a written or spoken report about something that has happened บันทึกถ้อยคำ
weapon – an object such as a knife, gun, bomb, etc. that is used for fighting or attacking somebody อาวุธ
compile – to collect information from different places and arrange it in a book, report or list รวบรวม
murder – the crime of intentionally killing a person ฆาตกรรม
charge – an official statement accusing someone of committing a crime ข้อหา
press charges – lay charges; file charges; to accuse someone officially of committing a crime ตั้งข้อกล่าวหา
theft – (the act of) dishonestly taking something which belongs to someone else and keeping it การลักขโมย
illegal – against the law ผิดกฎหมาย, นอกกฎหมาย
detention – the condition of being forced to stay in a place การกักตัว
initial – early; first เบื้องต้น
eyewitness – someone who sees something happen พยานในเหตุการณ์
About the author
- Writer: Terry Fredrickson
Position: Education Marketing and Support Manager