DNA profiling has established itself as an essential tool in criminal investigations in the nation, 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, the 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 from 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 about 1.15 million from suspects were registered, with around 3,500 of them matched annually after inquiries during investigations of further crimes.

The data base contains DNA samples from cold cases, including the 2000 murders of four family members in Tokyo. Such cases could be resolved suddenly with the help of DNA analysis, a senior official of the MPD said.

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.

Speech