A Japanese woman was arrested Wednesday on suspicion of involvement in her daughter's death after police discovered five bodies in an apartment this week.
Chizuko Okamoto, 54, was arrested on suspicion that she strangled her 19-year-old daughter, Rikako, to death in an apartment outside Tokyo, said Kanagawa prefectural (state) police spokesman Motoyasu Ito.
Police on Monday found the bodies of Rikako Okamoto, her three infants and her 35-year-old husband in the same apartment in Hiratsuka city, 60 kilometers (37 miles) southwest of Tokyo, Ito said.
The husband was found hung to death, but it wasn't immediately clear how the infants died, Ito said. The husband's mother initially found the five bodies when she visited the apartment on Monday.
Chizuko Okamoto told police she had lived in the apartment until March, according to public broadcaster NHK.
Police initially believed the parents killed their children then committed suicide, but evidence was later found suggesting Rikako Okamoto was murdered, Ito said.
Ito said police were investigating whether Chizuko Okamoto was involved in the four other deaths as well.