In recent years, there has been a large decrease in the number of cases in which police are able to track down theft suspects, partly due to growing difficulties in obtaining confessions about similar crimes they had previously committed, according to this year's National Police Agency white paper.
In 2013, investigators were able to take action against such suspects in about 250,000 cases. They comprised offences against which the police were able to take action during the initial investigation and those they tracked down after obtaining confessions from suspects about previous related crimes. The figure showed a decline of 190,000 from 2004, according to the police white paper released Friday.
The reduction can be attributed to the increasing difficulties involved in police investigations into theft cases due to societal changes. Such crimes account for more than 70 per cent of reported criminal offences.
The decrease included 140,000 cases involving offences against which the police tracked down after obtaining confessions from suspects about previous related crimes.
Such previous related crimes, which suspects confessed to during investigations of other charges, constituted 58 per cent of all detected crimes in 2004, but the figure fell to 46 per cent in 2013.
In cases where suspects being investigated for a crime later confess to additional crimes, there is often less eyewitness information and evidence than in cases where suspects were arrested on the spot or in similar circumstances. As a result, confessions have often been the key to successful investigations in such cases.
According to the white paper, among crimes which were later found in the process of investigations into other cases, 95 per cent were found because of confessions of suspects under investigation into other cases.
But recently, there have been an increasing number of cases in which suspects have denied the charges for which they were arrested. There have also been more suspects who have refused to confess to previous related crimes.
Investigations into such suspects have been more difficult, the white paper said.
The number of additional crimes found has fallen partly because investigators have been unable to spend sufficient time questioning suspects, according to the white paper.
Criminal trials in recent years have begun to place greater weight on concrete evidence, which have been more effective in proving crimes than suspects' confessions, according to the NPA.