A woman whose 43-year-old daughter is under arrest for trying to kill her died Friday of heart failure and congestive lung failure.
Shigeko Nishimae, 66, died at a hospital in Tenri, Nara Prefecture, where she had been undergoing heart disease treatment since September. Her daughter, former Nara nurse Yukiko Sakanaka, allegedly tried to kill her by feeding her the asthma drug salbutamol sulfate.
Nishimae's death, however, is not believed to be linked to the drug. She was suffering chronic heart disease and had several heart attacks since March.
Sakanaka was first indicted for attempting to murder her 15-year-old daughter by giving her food and drinks laced with the asthma drug. She was later served a fresh warrant last month for allegedly trying to kill her mother with the same drug on July 7 and 8.
Investigators believe Sakanaka attempted the two murders to collect life insurance money. She was the beneficiary of a 30 million yen policy on her daughter.
Both the daughter and mother were hospitalized after experiencing quickened heartbeats and trembling hands -- symptoms indicative of an overdose of the drug. The nurse's father was also reportedly hospitalized in June suffering the same symptoms.
Sakanaka's other daughter died in March 1997 at age 9 at a hospital in the city of Nara, while her son died in November that year at age 15 at a hospital in Tenri.
The son died of an accumulation of fluid in the lungs and brain. The daughter died of an accumulation of fluid in the lungs. The deaths were not probed, but Sakanaka reportedly received 200,000 yen in insurance on the daughter and 20 million yen on the son.