The Fukuoka Prefectural Police said the ranks of the Kyushu-area yakuza group Kudo-kai, including members and associate members, have decreased by 80 from a year before to 870 at the end of last year.

The police believe the number will decline further due to the major campaign they are waging to crush the group, which has attacked people who have cooperated in the fight against the underworld.

The police also said no shooting incidents occurred in the prefecture last year for the first time since they began compiling data in 1970.

Members and associated members of the Kudo-kai totaled 1,010 at the end of 2012 and 950 at the end of 2013, according to the police.

However, the police said an undisclosed number of Kudo-kai members were newly found in Tokyo and Chiba Prefecture in addition to those previously discovered in Yamaguchi and Nagasaki prefectures. The number of members located outside Fukuoka totaled 80, the police said.

Last October, prosecutors in Fukuoka indicted the group's two top bosses in connection with the 1998 fatal shooting of a man in public and 14 others on charges of attacking a nurse with a knife in January 2014.

Some 530 riot police members were deployed to Kitakyushu from around the nation at the time when Kudo-kai boss Satoru Nomura was arrested in September, but Fukuoka police head Masato Higuchi said this week that all of them had returned to their jurisdictions by the end of last year.