Wiretaps last year led police to arrest 39 people in 10 criminal investigations, including into drug-trafficking, a government report said Friday.
The report, adopted at a Cabinet meeting, said six of the 10 cases involved drug-trafficking or illicit imports, while the other four included one murder involving yakuza and one incident of gun use.
Police wiretapped a total of 9,028 telephone conversations, as authorized under a law that took effect in August 2000. In addition, police arrested 20 people last year in three investigations in which wiretaps were used in 2011, according to the report.
The 2000 law requires the government to submit a report on criminal probes that involve wiretaps to the Diet every year.