The National Police Agency has been implementing a phased plan to construct a database of DNA patterns of suspects and convicted criminals to facilitate criminal investigations. DNA patterns, also called DNA fingerprints, can identify individuals almost as accurately as real fingerprints. A 2002 Interpol poll of 127 countries revealed that 41 countries had DNA databases and 27 others planned to establish databases within five years.
Under the NPA's DNA information-collection method, the chance of two people having an identical DNA pattern is one in 180 million. DNA pattern information consists of a combination of alphabetical letters and numerals derived from an analysis of DNA fragments that are unique to each individual. In August 2003, the NPA distributed automatic DNA fragment analyzers capable of analyzing nine DNA fragments to prefectural police headquarters nationwide. The police hope to increase accuracy in the future by analyzing 15 DNA fragments.
A DNA data bank can improve the effectiveness of criminal investigations. But it can also pose problems involving privacy rights and human rights. The implementation of the plan, therefore, requires legislation that defines the entire process, from the collection of DNA information through its use in criminal investigations.