Police last year eavesdropped on electronic communications in 10 separate investigations, the Justice Ministry said Friday. The cases led to 101 arrests.
Nine of the cases were related to the alleged trafficking of illegal drugs, while the tenth involved an attempt on a person's life, the ministry said without disclosing details.
Phones, faxes and email are subject to court-approved surveillance under the wiretapping law. However, all interceptions last year were all of mobile phone conversations.
Ministry figures show 640 people have been arrested in 109 cases since the law was implemented in August 2000.
The law limits eavesdropping to four types of suspected crimes — drugs, firearms, contract murder and human trafficking. However, the ministry has submitted amendments to the Diet to add nine other categories, including regular murder, arson, fraud and theft. The revisions would also allow the police to intercept communications without having phone company personnel present.
The ministry hopes that the amendments will become law during the current Diet session, which ends June 1.
Some criminal law experts have expressed concern about implications for privacy with the expansion of permitted interception.