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About the prosecutors

A fingerprint on a dusty windowsill – the sole evidence used in nabbing the accused of a housebreaking incident. “That case stuck with me because of how meticulous the crime scene experts were,” Ms Grace Lim recalls from her time as a young prosecutor.

“I wanted to be a police officer,” she also shares. However, her parents thought that it was a risky job. In turn, she applied for law school, and was pleasantly surprised that “mooting and cross examination were quite fun”.  

Following a degree in law at the National University of Singapore (NUS), Ms Lim became a Deputy Public Prosecutor (DPP) at the Attorney-General’s Chambers (AGC), where she joined the State Prosecution Division, and was later posted to the Financial and Technology Crime Division. She then held an appointment of Director (Legal) at the Health Sciences Authority (HSA).

Currently, she takes on the role of a Deputy Director in the Crime Division of the AGC and specializes in financial crimes.

Also with us is Mr Eugene Lee, a senior state counsel at the AGC, now primarily prosecuting sexual crimes. He is concurrently an esteemed lecturer in forensic science at NUS.

When asked about his most unforgettable case involving forensic science, Mr Lee hesitates, “quite difficult to say”. At our insistence, he reveals that it was the first case he handled as a prosecutor, a grievous murder at the Drug Rehabilitation Centre. Provoked by the deceased over a game of table tennis, the accused covertly “sharpened his toothbrush into a sharp point”. It was then used as the fatal weapon which pierced the deceased’s carotid artery, regrettably leading to his death. “The blood spatter was all across the wall,” Mr Lee recalls.  

On what was the most impactful, Mr Lee recollects words from the deceased’s family, “Thank you for seeking justice for my son.” “And that I remembered all my life. It is all about seeking justice for people,” he says.

Role of prosecutors

Although fiction and television might make it seem that prosecutors who specialize in a certain field will only be assigned cases in that cluster, the reality is much more fluid. A prosecutor who primarily does homicide cases can be assigned a sexual assault case, or even a financial corruption case from another cluster. “Even though I specialize in corruption, I have just been assigned to assist in a capital drug trafficking trial,” Ms Lim shares.

“While the subject matter of what we handle is different, the type of work that we do is really not that much dissimilar,” she explains, describing the way cross-handling occurs on the job. “We look at the files that come in and assess whether there is sufficient evidence collected by the police or other investigative agencies to make out the charge. Then we decide whether to charge, warn or take some other action against the offender. We render advice to law enforcement agencies as well,” she adds.   

The only difference between being a prosecutor and a lawyer in a law firm, Ms Lim jokes, is that prosecutors cannot decline cases. Mr Lee qualifies this by adding that DPPs do so in special circumstances, such as when the accused is known to them. They would then declare the existence of a personal interest for impartiality’s sake. Notwithstanding such conflicts of interest, prosecutors generally do not decline cases, and are assigned cases based on “their level of seniority and how complex the case is”. 

Use of forensic science in cases

Many cases require some degree of forensic science. The classic application of forensic science is common in homicide, drug and sexual offence cases, with digital forensics having a paramount role in modern investigations.

What exactly is digital forensics? Mr Lee summarizes it as investigations relating to mobile phones, email correspondence, social media and other digital platforms that likely hold valuable information concerning the case at hand. Not only will there be a sheer amount of evidence to go through, much of it is often irrelevant, making it an extremely tedious exercise. “Sometimes you strike a gold mine,” he points out, with the discussion of crimes captured in online correspondences, but such occurrences are rare.

Ms Lim also remarks, “Digital forensics is like a workhorse, we use it to plough through all the evidence and tie together the threads of different things one has.” The need to synthesize is thus imperative in digital forensics.

Ms Lim illustrates this with the case of Public Prosecutor v Ding Si Yang [2014] SGDC 295. Ding, the accused was found guilty of providing “girls” to three Lebanese referees in exchange for match-fixing. The incriminating evidence was collated by sieving through the match-fixer and referees’ emails and WhatsApp messages. It revealed how they were introduced to each other and the type of corrupt offers made. The match-fixer’s call logs were also used to corroborate how and when the girls were provided to the referees. As Ms Lim sums up, “The digital evidence in the form of emails, messages, and call logs were thus important evidence that helped to piece together and explain the purpose of disparate meetings between the key players.”

Undoubtedly, with the prevalence of smartphones, even in cases like murder and rape (which physical evidence predominates), one cannot exclude the use of digital forensics, with “phones now important in every single type of crime handled”.

Expert witnesses

In relation to presenting forensic evidence in court, the role of expert witnesses is vital. Prosecution evidence is for the most part processed by forensic scientists from HSA. Sometimes, external consultants are also involved. Before forensic scientists testify in court as expert witnesses, they have to be trained. “With their basic knowledge of law from the TV, they have to go to court and testify. That’s not enough,” Ms Lim says.

HSA has their own internal training to help expert witnesses better understand the court process, and the legal department also steps in to run mock testimony practices for them. “My role in relation to expert witnesses is really to advise them on the law and help them to understand the whole criminal process,” Ms Lim adds, providing an insight into her experience in training expert witnesses as a former Director of the legal department at HSA. 

Apart from addressing questions expert witnesses often have, her role includes analysing the reports expert witnesses have prepared and predicting possible issues that might arise. More importantly, she arranges mock testimonies for the expert witnesses. “They are trained in Science while lawyers are trained in law, and when we come together, we need to understand what each other is doing,” Ms Lim shares. 

She then points out, “As legal counsel when we try to do the mock testimony for them, we have to come out with the facts. Otherwise, it is impossible to do any sort of examination-in-chief or cross-examination without a case theory.” This comes with the fact that the expert witnesses have no knowledge of the background of the case to ensure impartiality.

Perhaps the most important in a mock testimony is restricting the use of extensive technical jargon by expert witnesses. “Forensic scientists must be able to explain the concepts in a simple manner such that lay persons with no background in Science will be able to understand,” Mr Lee says. With the prosecution, defence and judges comparatively having a limited understanding of Science, it is essential for expert witnesses to explain their analysis in a simple manner.

However, “It is not easy for them because they speak to each other every day in jargon. Lawyers use the terms like ‘negligence’, and ‘ameliorating the damage’. It is the same problems that scientists will have,” Ms Lim remarks. Also, “Singapore is quite insulated in this aspect,” Mr Lee adds. “In the US, they have a jury system, and they are neither trained in science or law, so the explanation has to be simplified even further, or the jury will not be convinced.”

Moreover, expert witnesses have to deal with the pressure of being in court. As such, part of the training includes “making sure they are more confident, that they can explain themselves clearly and be unrattled by the barrage of questions coming in from different angles. There won’t really be concerns with the content of their work, but more of how they carry themselves in court. Little things to tweak their presentation, ensuring that their evidence comes across as convincing,” Ms Lim says.

Prosecutors also have a role in preparing expert witnesses. Mr Lee explains the process, “First, they come up with a report. After we read through the report and if we need clarification from them, we will set up an interview with them and ask them about specific parts and sometimes when we realize that the particular issue may be very complicated, we might ask them to create slides to help present that concept in court.” Certain aspects of their testimony are then evaluated, like the extent of technical jargon being used, how the results were derived and whether there is any possibility of mistake.

However, such discussions can only happen after the expert witnesses have done their analysis and written their final reports. “We only talk to them after that to understand what they are doing for the trial.” Notwithstanding the liaison between the HSA and the prosecution in prepping the expert witnesses for trial testimony, both parties still work relatively separately. Singapore’s criminal justice system is such that the scientists in HSA are insulated from the criminal investigations, so that they can maintain their independence in arriving at their scientific conclusions.

As Ms Lim explains, “It’s not like TV where you see the prosecutors, police and scientists sit together to discuss what to put in the report. Because they are experts, they have to have their own opinion and do the analysis themselves and be able to back it up.”  

Challenges in the use of forensic science

In using forensic science as the basis for evidence, it is foremost imperative for everyone to come to the same understanding. However, it is often not the case. “People make a lot of assumptions about Science because if you know a little bit of Science, you kind of jump the gaps between understanding and assuming that if I know theory A, it should apply the same way to what the scientist is talking about that is kind of similar. But that may not necessarily be true,” Ms Lim says. 

To this, Mr Lee concurs, illustrating this with a High Court case that he handled. “There was a lot of blood over. They swabbed for DNA, but there was no DNA. So the judge said, how come there is no DNA?” he says. The answer lies in the low proportion of nucleated white blood cells in blood available for DNA extraction. “The judge did not know this. A lot of assumptions are made about Forensic science because of CSI. Previous episodes of CSI are very inaccurate.” It is thus imperative for mock testimonies to be arranged so that scientists are aware of explaining the step-by-step process of their analysis, debunking any possible assumptions made.

To narrow the scope of discussion, we further explored the limitations of both DNA and pattern recognition evidence. 

DNA evidence

The media quite glorifies the use of DNA analysis in solving criminal cases. Almost everything can be solved by a single DNA swab, with instant results. The reality, however, is quite different. 

To begin, Mr Lee points out, “DNA is obtained from the nucleus of cells, and cells will die with exposure to bacteria, heat and UV lighting.” DNA evidence is thus ideally analysed as soon as possible. However, if HSA is overwhelmed with many cases and the submission of multiple exhibits, it will take a long time to process the samples.

To avoid compromising on the integrity of DNA, the evidence is stored in the fridge. However, this cannot account for how long the police takes to the find the piece of evidence, swab it and send it to HSA for analysis.

Ms Lim adds that with forensic evidence, there is usually a “trade-off between accuracy and reliability against how quickly the results can be obtained”. Rapid DNA analysis can definitely be done, but parties might be uncomfortable using such results in court. Explanations will have to be given to further convince the court that the results are reliable. Instead, a thorough analysis done over a longer period of time would most likely give fool-proof results.

Similarly, for digital forensics, a brief preview of mobile phones and hard drives can produce useful information. However, information hidden in encrypted folders or deleted can only be found through a fully digital forensic analysis where the information is put through a forensic software, allowing a complete investigation.

Mr Lee then advises that DNA evidence is not an absolute requirement in cases. “In the 90s, we did not use forensic evidence, we used confessions due to the limited forensic evidence one could obtain,” he explains. However, in the past decade, the focus shifted to the use of forensic evidence in court, where judges prefer objective evidence to verify the veracity of witness testimonies.

Mr Lee remarks, “DNA evidence has only one purpose – to link the suspect to the victim by the showing that the suspect was at the scene. Other than that, DNA cannot tell you what the suspect did, what time the suspect was there, and how long the suspect was there… In most cases, DNA evidence does not really play a crucial role that makes or breaks the case.”

He illustrates this with the case of Public Prosecutor v Wang Wenfeng [2011] SGHC 208, which he personally worked on. In this case, the accused’s DNA was not found in the taxi in which the deceased was killed. The defence then attempted to argue that the deceased stabbed himself, which led to his own death. However, despite the lack of DNA evidence,  the accused was eventually found guilty of murder. Evidently, “Forensic evidence cannot be seen in isolation. It has to be seen in the wider context, regardless of whether it aids the prosecution or the defence.”  

Pattern recognition evidence

Apart from DNA evidence which is perceived as the gold standard of forensic science, there are other forms of evidence, like pattern recognition. Pattern recognition evidence broadly encompasses fields like tool marks, bite marks, firearms analysis and even fire reconstruction.

The use of pattern recognition evidence is however controversial, with courts pushing for a statistical basis of such evidence, as can be applied to DNA. “Unfortunately, all the pattern recognition experts are largely unable to come up with such statistical basis, causing it to be termed ‘junk science’,” Mr Lee remarks.

A prime example is bite marks. Although Mr Lee highlighted that bite marks can be individualistic, Ms Lim points out that “It would be almost impossible to conduct a thorough study on the whole universe of bite marks, and thus a statistical analysis would be very difficult to do.”

Regardless, Mr Lee shared that bite marks may be relied on for elimination rather than specifically identifying a suspect as the accused. He specifically referred to the case of Public Prosecutor v Sundarti Supriyanto [2004] SGHC 212. In this case, there were bite marks on the accused, and three persons who could have inflicted them: the employer (deceased), a toddler and an 18-month-old baby. The accused claimed that the bite mark belonged to her employer, but after close examination, forensics experts ruled that the size of the bite mark belonged to a toddler rather than an adult. The bite mark evidence was thus used to discredit the accused’s account.

Nevertheless, compared to bite mark evidence, fingerprint evidence is widely regarded to be a reliable form of pattern recognition evidence. In fact, “Fingerprints have become the accepted standard for identification by the government, banks, and even handphones.” Since fingerprints are individualistic, it would also be simpler to do a statistical analysis compared to bite mark evidence.

Forensics in Singapore and the United States of America

We also took this opportunity to ask Mr Lee about his experience in the US, where he studied forensic science under Dr Henry Lee, a renowned Taiwanese-American forensic scientist. Mr Lee identified two key differences between the practice of forensic science in Singapore and the US.

Firstly, it is relatively easy for the defence to obtain forensic experts in the US. In Singapore, however, forensic experts from HSA largely work with the prosecution and the police. The defence has access to a smaller pool of forensic experts and they may even need to engage forensic experts from overseas.

Secondly, “Prosecution expert evidence is constantly being challenged in the US, ” remarks Mr Lee. US attorneys tend to attack not just the forensic reports, but the expert witnesses themselves. There are even courses organised by defence lawyers on how to tackle forensic experts, starting with the report, then quickly moving on to the “witnesses’ history, work and love life”. The situation is such that more forensic experts in the state and federal courts are afraid of being sued. Although such a phenomenon is not currently present in Singapore courts, Mr Lee cautions that this practice might be gradually adopted here.

Future of forensic science

How will the use of forensic science in Singapore continue to develop? Mr Lee believes it will become more commonplace as prosecutors increasingly rely on forensic science to prove that their “evidence is objective and reliable as possible”.

“Of course, we have to go with the times,” Ms Lim adds, explaining that with the increasing expectation to use forensic evidence in court, the onus is on the prosecution and HSA to produce such evidence in trial.

Concluding remarks

Although both Mr Lee and Ms Lim acknowledged that their journey as prosecutors is not smooth sailing, their purposeful work is what keeps them going.  

“I persevere and think that the work is very meaningful. It is something that we do, to give people a voice,” Mr Lee says. Ms Lim then adds, “The work that I do has an impact on real people, their lives, the people around them. I think it is very fulfilling when you see victims getting justice.”

As a concluding statement, both our guests shared that if you are interested in forensic science and want to deal with it on a more regular basis, the AGC is the place to be.

We would like to extend our utmost gratitude to both Mr Lee and Ms Lim for taking their time out to be part of this meaningful interview.

Authors’ Biography

Jeslyn Tan is a Y2 student at the NUS Faculty of Law. She is currently part of the Criminal Legal Aid Scheme, helping lawyers with pro bono criminal cases. She is also a part of CJC Forensics. In her free time, she enjoys reading fiction novels.

Phoebe is a final year undergraduate with a major in life science and a minor in forensic science. To pursue her passion in forensic science, she joined the NUS Criminal Justice Club.