Police arrested four members of the same extended family Wednesday in a multiple murder investigation that has transfixed Japan, an official said.
Newspapers and television news programmes have offered extensive daily coverage since three decaying corpses were found in an empty house in Hyogo prefecture in the west of Japan several weeks ago.
A fourth body encased in a concrete-filled drum was pulled out of the sea west of Hyogo earlier this week as police said more people were missing, presumed dead.
The main suspect in the case — a 64-year-old woman called Miyoko Sumida who used to live in the abandoned house — has been in custody since early in the probe, which began last year.
Officers on Wednesday re-arrested Sumida and arrested her 62-year-old common-law husband and her two sons, aged 30 and 25.
They also arrested a 42-year-old man married to one of the women whose body was found in her house, a force spokesman said, taking the total number of arrests to five.
Police have obtained arrest warrants for three others and were due to arrest them Wednesday, the Mainichi Shimbun newspaper and other reports said.
All four dead were related to, or acquainted with, the chief suspect, reports have said.
News coverage of the case has featured tangled family trees and speculation over the reasons behind the multiple deaths, which has centred on claims the family has large debts and hinted at the involvement of organised crime.
Japanese press frequently report details of police investigations that would be considered prejudicial in other countries.
The case has been particularly high-profile because crime levels are comparatively low in Japan, where social order is highly prized.
Four arrested in Japan murder case
