Police across Japan conducted authorized wiretaps in a record 11 cases in 2008, up four from the previous year, that lead to the arrest of 34 people, Justice Minister Eisuke Mori told a Cabinet meeting Friday.
The number of arrests was the same as 2007, the Justice Ministry said.
The wiretapping cases targeted mobile phone conversations mainly in connection with illegal drug sales and illegal possession of guns. Wiretapping in these cases lasted from one day to 30 days, the ministry said.
Apart from the 34 arrested, the police arrested seven others in 2008 based on wiretaps conducted in 2006 and 2007 in connection with three cases.
"Knowhow on authorized wiretapping seems to be steadily taking hold," a ministry official said.
The Communication Interception Law, which authorizes wiretapping as part of investigations, took effect in 2000.
The Metropolitan Police Department carried out Japan's first wiretap authorized under the law in 2002.