Forensic Evidence – Revealing the Unseen Facts

If you’ve ever watched ‘CSI’ or other television shows, you already know how popular forensic science has become as a profession.   Forensic evidence plays a crucial role in forensic investigations.  It is not, however, easy to collect and analyze.  Forensic evidence is often present in very small quantities, making it difficult for detection by human senses, and too often difficult for standard analyses.

Fortunately, new innovative scientific tools and multidisciplinary approaches are being developed here in the ASEAN region to overcome these difficulties.   Let me give you two examples of how my work in forensic science is helping law enforcement in Thailand.

Cannabis sativa L. is a well-known narcotic plant, and declared illegal under the laws of all ASEAN member states.  However, its seed is a rich source of essential fatty acids, and the plant also produces quality industrial fiber.  Due to these characteristics, the cultivation of the ‘fiber-type’ ofCannabis sativa L., which contains ‘no’ or ‘very low’ quantities of the narcotic substance tetrahydrocannabinol (THC), is authorized in many ASEAN countries, while the cultivation of the narcotic ‘drug-type’ of Cannabis sativa L. remains outlawed.

‘Drug-type’ Cannabis sativa L.
‘Drug-type’ Cannabis sativa L.


In 2008, cultivated ‘fiber type’ Cannabis sativa L. was reported in Thailand for legal use.  But how can trade and law enforcement officials tell the difference between it and the illegal variety?  Officials were justifiably concerned that drug dealers could try to mask the illegal ‘drug-type’ ofCannabis sativa L. as the legal ‘fiber type’ of the plant. Field tests were difficult to administer, and results sometimes suspect.

In response, my colleague and I developed a DNA test to distinguish the ‘drug-type’ from the ‘fiber-type’ of Cannabis sativa L.  This DNA test, which tests for the genetic code that is unique to the plant type, can now be used as an alternative or complementary test to the standard chemical test to detect the narcotic THC.

Another example is the development of multipurpose powders to recover and enhance fingerprints at crime scenes.  Typically, dusted latent fingerprints are examined using the common ‘Automated Fingerprint Identification System’, or AFIS. AFIS works by matching the unknown fingerprint pattern with the database of known fingerprints. The quality of fingerprints recovered from the crime scene is very important. If only a partial print is recovered, the value of evidence diminishes. The development of multipurpose powders allows latent fingerprints to be “dusted” to evaluate their genetic identity.  This new technology therefore helps increase the evidential value of fingerprints found at a crime scene.

High quality forensic science work can be very challenging, but when based on sound scientific methods, can provide reliable evidence to assist the courts and minimize the chance of wrongful convictions.  And while the use of forensic scientific analysis might look ‘sexy’ on television, real innovations in the forensic sciences are taking place every day, including here in the ASEAN region.

If you are interested in learning more about the forensic science research being conducted at Mahidol University in Thailand, please visit:

About the author:  Nathinee Panvisavas, PhD, is an Assistant Professor of Forensic Science at the Faculty of Science, Mahidol University in Bangkok, Thailand.