Three men were arrested Monday and a fourth is being sought in connection with the slaying of an elderly couple at their home in Nishigoshi, Kumamoto Prefecture, last Sept. 1, police said.
Arrested were Hideo Kuzuya, 38, Yuichi Ichiyanagi, 37, and Hideki Shinohara, 31. Still being sought is Kazuhiro Kokubo, a 31-year-old gangster with the Inagawa-kai crime syndicate.
According to police, the four conspired to rob the house of Mitsuru Kan, 82, and his 73-year-old wife, Matsuyo. She died from wounds caused by what apparently was a metal ball fired from a remodeled air gun, while he died of head and other injuries.
Kuzuya told investigators the four had targeted another house to rob but mistakenly went into the Kan house, police officials said.