Police have located the mother of a boy whose skeletal remains were found last week in a trash-filled apartment in Atsugi, Kanagawa Prefecture, sources familiar with the investigation said Tuesday.

It is suspected that 5-year-old Riku Saito starved to death in early 2007. Police on Saturday arrested his father, Yukihiro Saito, 36, and launched a search for the boy's mother. They have now interviewed her.

They said they plan to investigate whether the woman, who is currently working in the Tokyo area, knew about Riku's neglect at the hands of his father.