DNA Profiling Established as Key Police Tool in Japan

Tokyo, Jan. 3 (Jiji Press)--DNA profiling has established itself as an essential tool in criminal investigations in Japan, due to its vaunted accuracy in individual identification. The number of DNA tests in criminal probes has soared more than 10,000 times since the method was put into full use in 1992, according to the National Police Agency. The accuracy of identification has improved drastically in the meantime, raising hopes for clues to solve cold cases. In November 2018, Tokyo's Metropolitan Police Department arrested a man on suspicion of assaulting a woman in March 2010. The arrest with an eight-year delay came after DNA samples collected from oral cells of the man when he was seized in a separate case matched those taken from the clothes of the woman. The NPA started in 2004 operating a data base of DNA samples from articles left at crime sites and suspects. As of the end of November 2018, about 36,500 samples from articles and some 1.15 million from suspects were registered, with around 3,500 of them matched annually after inquiries during investigations of further crimes by suspects. The data base contains DNA samples from cold cases, including the 2000 murders of four family members in a central Tokyo residential area. Such cases could be resolved suddenly with the help of DNA analysis, a senior official of the MPD said. Japanese police first adopted DNA analysis in 1989 and put it into full use in 1992. In step with technological advances, the annual number of DNA tests conducted in criminal investigations has totaled about 300,000 annually in recent years, compared with 22 in 1992. Its accuracy has also improved, to a level of one to 4.7 trillion. The use of DNA profiling has worked the wrong way in the past, however. Over a May 1990 murder of a girl, 4, in eastern Japan, the wrong man was convicted as police relied too much on the results of a DNA test that had the identification accuracy of only 1.2 to 1,000, meaning that it pointed to as many as 12 people from among 10,000 people. Later, a DNA test was conducted at the current accuracy degree of one to 4.7 trillion, and the man was released from indefinite imprisonment in 2009 and acquitted the following year. Masaki Hashiyada, associate professor at Kansai Medical University, who is familiar with DNA profiling, said articles left at crimes sites may include those of unrelated people. "Instead of trying to identify suspects by DNA samples alone, it is necessary to use other pieces of evidence in investigations," he said. END