In view of the very high-profile court case that is on trial in Malaysia currently that even caught the attention of international community, I think it is of public interest that I share some of my views on what should a chemist (more specifically a ‘biochemist’) prove beyond reasonable doubt on the DNA evidence involved in this type of case.

To prove a case of ‘carnal intercourse against the order of nature’ and more specifically ‘anal sex’ in this case, the prosecutors have to provide strong evidence that the sexual organ (the penis) of the suspect did inserted into the accuser’s anus. Since the prosecution are still going ahead without the medical evidence on their side, I think the prosecutors are placing their hope and seek to rest their case on so-called ‘DNA evidence’.

However, to prove that any DNA data is evidence beyond reasonable doubt is not as easy as we (or the prosecutors) may have thought. Especially in this kind of high-profile case and without first having any conclusive medical evidence at hand. Since the suspect and his team of advocates have raised many possibilities and even a conspiracy of the highest level, the biochemists should carry out their tasks in respect of all possibilities and perform a series of analyses to exclude or confirm all possibilities.

Besides, many questions and doubts that have been raised from the public, mainly on the integrity of the specimen and whether it would be still possible to collect any semen specimen from the accuser’s anus or rectum after more than 48 hours from the alleged time of the crime. In my opinion, these are valid questions that require the prosecutor’s expert witnesses to answer with documented data. Here, I will give some other views that may serve as informative knowledge for the general public.

First, since the charge is of ‘carnal intercourse’, the DNA material should be produced from the sexual organ, and not from any other organ, tissue or cell of the suspect. Since the suspect already used the alleged apartment, his tissue or cells may have landed onto the accuser’s body either from the environment or from any other personal utensil like toilet paper or a towel.

Thus, the biochemist must provide detailed data on how the specimen was determined as semen (seminal fluid) and not just stains, tissue, fluid or cells from other parts of a human body.

To determine that a specimen is semen is very simple. Besides some chemical tests, the most reliable, direct and confirmatory test done is by observing the presence of spermatozoa (the mature male sperm cells) under a light microscope. And any trained biologist or medical scientist can easily perform this. Failure to present a documented prove on this microscopic examination will be a fatal blow to the so-called ‘DNA evidence’ as it will be totally no value in helping to prove the case of ‘carnal intercourse’.

Secondly, the extraction of the DNA material must be specifically and purely from the spermatozoa, and not from the whole mix of seminal fluid which may include other cells or even other DNA matrix in the fluid or stains, other than spermatozoa. This is to exclude any possibility that the DNA extracted is from a contaminated source, or even DNA matrix that have been ‘intentionally mixed’ in the seminal fluid.

This is highly possible in view of the high-profile nature of this case. Let me explain on how this can easily be done.

A person’s DNA material can be easily collected and extracted and it may be from saliva, sputum, hair, skin, blood etc, and even from a very old sample stored in proper conditions. Although the amount may be very minute, the DNA material can be extracted from even a few cells, than amplified with the Polymerase Chain Reaction (PCR) technique. The PCR technique and facilities for it arecurrently widely available in many laboratories in Malaysia.

Practically, a few copies of DNA matrix can be multiplied in millions of copies of identical DNA matrix. So this highly concentrated but ‘artificial or cloned’ DNA material can be mixed with the accuser’s own seminal fluid than planted on the site required.

If the DNA analysis was done from the collected specimen which had been mixed with the ‘artificial’ DNA, or just mixed with enough amount of the suspect’s cells or spermatozoa, then the result will show the existence of the suspect’s DNA and the accuser’s DNA. The presence of the accuser’s DNA can be easily explained since the specimen is collected from his own body or his personal belongings.

Thus, to exclude this possibility and to present the DNA evidence at a level of certainty, the DNA extraction must be done purely from the spermatozoa and not from the whole mixture of the specimen or any other component or cells of the specimen.

The separation and isolation of spermatozoa from a mixture is also a simple technique that can be done by most biological laboratories. Currently, there are a few more advanced techniques in identifying and separating the sperm’s DNA with a higher throughput and higher sensitivity. So, I think our National Chemistry Department should have no reason for not performing this procedure before carrying out the DNA extraction, analysis and profiling.

Such a procedure is also recognised as an international standard practised by many forensic agencies and usually termed as ‘differential extraction’ of DNA. A failure to do so will not be reasonable and will make the DNA evidence inconclusive and absolutely doubtful.

Thirdly, there are even speculations that ‘they’ used the specimen from the 1998 case to ‘plant’ it back on the accuser’s body and thus fabricate the ‘DNA evidence’. However, I am not aware of any detailed news report on the 1998 case that mentioned that the stains on the mattress were confirmed as semen with the presentation of sperm cells or just ‘stains’ from a human source that contain DNA material.

I do not think the Chemistry Department ‘officially’ obtained any semen specimen in the 1998 case, as the suspect never ‘officially’ submitted any semen specimen but just blood or buccal swab specimen. However, if ‘someone’ did possess the suspect’s semen specimen, then it will be somehow a difficult case for the present defence team.

Anyway, with the current development in human reproductive technology and sperm-banking, there are numerous detailed documented studies on changes in sperm cells after cryo-preservation (preservation by ‘deep freezing’) compared to normal sperm cells. Those changes can be termed as ‘cryo-injury’ when the sperm cells are subjected to ‘freeze-thawing’ in cryo-preservation.

The genetic integrity of the spermatozoa is still intact and suitable for fertilisation and DNA analysis after cryo-preservation even though there are many observable changes in the cells. If there is no local expert, foreign experts in this area (won’t be surprised if among them there are Malaysians working aboard) can be sought to verify this - whether the alleged semen specimen in the current case is a ‘new’ or ‘old’ specimen.

However, in view of the fact that the specimen remained at a very ‘hostile’ environment in the rectum or anus for more than 48 hours from the alleged time of crime, this question may remain unsolved and no conclusion can be made.

The paramount question is was there any ‘penetration’? Above all else, the best that ‘DNA evidence’ can do is to help establish the ‘who’ that was involved in the case but definitely not the ‘how’. There can be many ways for a person’s DNA to get into someone else’s anus.

By contamination as above mentioned, by purposely planting it via a sex toy eg, a dildo (artificial penis) with some lubricant or even simply injecting it via a syringe (without a needle). There are simply too many ways. Thus, even evidence of DNA from the spermatozoa of the suspect will be useless in making any conclusion on ‘how’ the semen went into the accuser’s anus.

The prosecutors have to first establish that there was a case of penetration then only ask on the ‘who’ by probing into other evidence like ‘DNA evidence’. Without conclusive evidence from the medical examinations, I wonder how the prosecutors will make their case on the penetration of the anus by the suspect’s penis.

Since the prosecutors expect their scientific experts to present some seemingly indisputable scientific ‘DNA evidence’, than please present it in a truly airtight scientific manner excluding or confirming any other possibility with scientific methods and available for verification by an independent third party. Like any other evidence, it should be able to be verified by others for if it is unable to be verified by other experts, then it shall not be called evidence or ‘scientific fact’.