Working for Evidence: From the Crime Scene to the Trial

Visualize this: A series of senseless murders terrorizes an otherwise serene private residential enclave. The bizarre cases bear an uncanny similarity: The victims, all young women, were found dead in swimming pools. And, as if so carefully schemed, the killers leave no traces of fingerprints at the crime scenes. Scientists at the local criminalistics laboratory work overtime in search of evidence. Physical examination shows that the victims were strangled before being pushed into the pools, but there are no other clear leads. Finally, microscopic analysis of rope fibers found at each of the murder scenes provides a crucial clue: All the murders were probably committed by the same culprit.

Sounds like a scene out of a TV crime series? Yes, but this is how forensic scientists working at criminalistics laboratories help solve criminal cases. Their role is to analyze physical evidence collected by law-enforcement personnel at the scene of a crime, to compare that evidence to evidence found on a suspect, and to provide expert testimony at legal trials in courts of law. By painstakingly examining evidence and sometimes helping in virtual reconstruction of the crime, they assist in making legal conclusions about what actually happened and who did it.

Clearly forensics is not as morbid as its name implies, and there's much more to it than cadavers and blood spatters. So, if you are the analytical type, fascinated by solving mysteries and with an eye for the unusual, you would likely find the job exciting and rewarding.

Indeed, to forensic scientists working at Singapore's only criminalistics laboratory (see box), there is no typical day. Every day brings its own challenges, and every case that comes in brings a new set of learning experiences. "The scope of service we offer is very wide, and so are the samples that come in for us to examine or analyze. Because of the varied nature of samples that come in, our work in the laboratory is very exciting, as no two cases are the same," says senior forensic scientist Angeline Yap Tiong Whei, who earned a Ph.D. in chemistry from the University of Cambridge, United Kingdom. Yap, who joined the centre in 1996, provides expert analytical services in areas such as drug analysis, trace evidence, arson, oil spills, miscellaneous organic compound analyses, obliterated stamped marks, shoeprints, damages, physical comparisons, and firearms.

Singapore's Crime Lab

The Criminalistics Laboratory is headed by forensic expert Tay Ming Kiong. It is a division of the Centre for Forensic Science within the Health Sciences Authority of Singapore and serves "to meet the investigative and forensics needs of the criminal justice system by providing reliable, error-free and timely forensic examinations and expert consultancies covering a comprehensive range of crime scene physical evidence." Name any sensational crime of the past decades, and chances are that the criminalistics laboratory has had a role in solving it.

According to Yap, forensic scientists normally begin work on a case with "a careful documentation of the sample that is submitted by the police." Depending on the type of examination or analysis required, she adds, "the documentation may stop at the gross macroscopic features or may go all the way to the individual microscopic features."

The actual excitement, Yap says, starts after this documentation is complete: "For firearms, we fire the live rounds so as to collect the bullets and cartridge cases for comparison. For arson cases, we put the debris or sample in a tin and heat it up overnight to allow any ignitable liquid to be absorbed into a charcoal strip. This charcoal strip is subsequently eluted with a solvent and analyzed by gas chromatography--alone or together with mass spectrometry. For tool-marks cases, we have to examine the imprints under a microscope, study the suspect tools, make test marks, and compare them. For assault cases, we do microscopic examination of the cuts or tears found on the clothing and determine whether they are recent cuts and whether they were caused by a single-bladed or double-bladed tool. We also look for the presence of foreign fiber and see whether we can match it to any clothing of a suspect. Sometimes, we also go down to the crime scene to advise the police on the type of evidence to collect."

Not surprisingly, there are challenging as well as satisfying moments. "The most satisfying part of the job is solving an unknown case: the thrill of looking at it from all angles, all aspects, seeking out relevant information, using various techniques, and putting all these jigsaw puzzles together," says Yap. Yap believes that among her most challenging cases was the widely publicized bunker-fuel contamination at the Port of Singapore: "We started with no prior experience at all and had to set up the distillation set from scratch, look for standards, verify experimental conditions, and work within a very tight timeframe."

For junior scientist Vicky Chow Yuen San, who joined the laboratory only in May 2000, every case is challenging and, for her, a learning experience. "Each case has its own uniqueness and presents different challenges," says Chow, who earned a first class B.Sc. (Hons) in materials science from the National University of Singapore. She specializes in analyzing trace evidence, obliterated stamped marks, shoeprints, damages, physical comparisons, gunshot residues, firearms comparison microscopy, glass, metals, polymers, explosives, and corrosive materials. To her, the most satisfying part of the job is when her "examination yields results" and also when she "goes to court and witnesses how her examination has contributed to the investigation."

"I think forensic science in Singapore is starting to establish itself," says Yap. "We first obtained accreditation from the American Society of Crime Laboratory Directors Laboratory Accreditation Board in 1996. This accreditation puts our laboratories on par with the other well-established international laboratories. In addition, we have a lot of opportunities to attend international conferences that put us constantly in touch with the fast-evolving forensic science field. This widens our exposure, updates our knowledge and techniques, and constantly propels us to excel in our work."

Other than having to look at "morbid" and "gruesome" evidentiary samples, Yap has no qualms about her career choice. After all, she says, "forensic science is a very exciting career which is definitely not for the faint-hearted or those who only follow instructions. On the whole, I would say that the career prospects for forensic scientists in Singapore are good, and I have absolutely no regrets about being a forensic scientist." Chow echoes her sentiments: "I think we have a lot of scope for future development. Forensic scientists will have excellent opportunities to participate in exciting developments. Through all the forensic developments, career prospects should be bright for forensic scientists in Singapore."

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