The New Taipei City Police Department’s Forensic Science Center is a the kind of quiet, unpretentious facility in which ­staffers are so  engrossed in their work that they say nary a word to one another. Officer Alex Chen greets us dressed in a white lab coat rather than a police uniform, and then begins showing us around the center. Though it looks like an ordinary science classroom, it is the only forensic laboratory in Taiwan to hold seven testing certifications, including ones for testing DNA and air guns.

Chen comes across as more scholar than policeman. A PhD in forensic science, Chen’s graduate studies included in-depth investiga­tions of ballistics and the muzzle energy of air guns that led to seven published papers. In more recent years, his focus has shifted to DNA: he has been running the center’s DNA lab for the last decade, and has published five papers in the field. Whether aiding criminal investigations or identifying unknown persons, Chen’s work and achievements revolve around the unique DNA signature of every human body.

The forensic examination of DNA is an important tool for criminal investigators.

Deciphering evidence

Having worked in forensics for more than 20 years, Chen illustrates the importance of DNA to policing by telling us about a case. In 2018, a decapitated body was found below Zhongzheng Bridge in New Taipei City’s Yonghe District. While the media obsessed over the method used to dismember the body, the actual investigation focused on more than 100 pieces of physical evidence found on the embankment and sent to the lab for study. There, Chen and his team painstakingly examined all of the physical evidence, and ultimately identified a small amount of the deceased person’s DNA on a knife left at the scene. That DNA proved crucial to cracking the case.

Having confirmed the knife as the murder weapon, the police were able to identify the shop that sold the uncommon German blade. They then obtained security images that enabled them to track down the buyer of the knife and the primary suspect.

Because the case also involved an injured dog, Chen first tested for human blood, which enabled him to exclude 50 pieces of evidence and quickly tie up the case. It turned out that the killer had also cut the nose of the victim’s dog, Lulu, during the attack, causing its blood to splatter all over the scene. The location of the blood helped the police rule out the possibility that the victim had been killed at home, and confirm that the crime had taken place on the embankment.

New Taipei City police officer Alex Chen is very experienced at gathering evidence from crime scenes. He often reminds younger investigators to be extremely conscientious while gathering evidence because they won’t have a chance to revisit the scene. (courtesy of Alex Chen)

A DNA database

Chen also uses DNA to help find missing persons. He tells us about the heartbreaking circumstances that got him involved.

When a man suffering from dementia became lost a dozen-odd years ago, his anxious family filed a missing person report with the police. Determined to find him, the family also visited a forensic research institute to create a DNA file. While this was happening, a con­scien­tious passerby found the missing man and escorted him to a New Taipei City police station. ­Un­fortu­nately, ­because the officers at the station couldn’t identify the individual, they categorized him as homeless and turned him over to the Social Welfare Department, which then placed him in a nursing home.

The man passed away five years later, becoming an “unknown decedent.” When his DNA profile was then entered into the Unknown Decedent DNA Database, it was matched to that of his family, which was still on file. When the family collected his ashes, they couldn’t help but wonder why the authorities who had found him five years ago weren’t able to return him to them while he was still alive.

Hou Yu-ih, then deputy mayor of New Taipei City, brought up the case at a meeting on missing persons in 2013. He asked participants why the family hadn’t been found while the man was alive, and ordered the relevant agencies to come up with a way to close the holes in the system. Chen subsequently served as lead author of the policy document that led to the collection and data­basing of the DNA of living homeless persons.

This initiative revealed that not all of the 41 homeless persons received into the New Taipei City system had been assigned to nursing homes in New Taipei City. Some had instead been sent to facilities in Hualien and Miaoli, forcing the DNA collection work to range farther afield. Recalling the situation, Chen remarks, “It’s no wonder their families couldn’t find them!”

When the DNA database came into operation in 2014, the first attempt at matching files unveiled the identities of nine individuals, located their families, and returned them home.

Comparative analysis of bullets and cartridge cases can provide useful evidence in cases involving firearms.

Fallen leaves returned to their roots

In 2019, Chen undertook another initiative to make families aware that they could place their DNA on file to help find missing relatives. He began by gathering the New Taipei City police’s pre-2011 data on missing persons, which yielded more than 490 reports. He and his colleagues then started making phone calls. Their effort ultimately led 65 family members of missing persons to place their DNA on file.

Meanwhile, the forensic institute’s Unknown Decedent DNA Database has identified 10 previously unknown persons who died by suicide or as typhoon casualties.

An old saying has it that “public service is a good place to improve oneself.” Alex Chen has done immeasur­able good by using DNA technology to reunite indigents and the silent dead with their families. He believes that it is important to help families find out what has become of their missing loved ones, no matter whether the news is good or bad, because it offers them closure, lifting the burden weighing on their hearts and minds, and allowing them to move on.

In-depth study of air-gun pellets resulted in a ban on the sale of toy guns with the power to injure.

Alex Chen’s conscientious study of the effects of temperature and projectile weight on the destructive power of air guns has enhanced the credibility of the forensic identification of guns.