Police arrested a 43-year-old practical nurse Sunday on suspicion of attempting to kill her 15-year-old eldest daughter to claim life insurance money, by giving her a drug-laced tea, police said.
Police said the woman's second daughter died in March 1997 at age 9 at a hospital in the city of Nara, and that her son died in November 1997 at 15 at a hospital in Tenri, Nara Prefecture.
Investigators have begun to look into those two deaths and have seized medical records and the boy's organs.
The eldest daughter, a senior high school student, is insured for 30 million yen, while the son in insured for 20 million yen, according to police.