**1. Outline of the Wakayama arsenic murder case**

Four people were killed by arsenic poisoned curry at a summer festival on July 25, 1998, and other 63 participants were heavily injured but survived though they ate the poisoned curry. It is still not well known whether some embryos or fetuses were included within 63 or not, because the personal data is not open. The arsenic intake was authorized by the arsenic analysis of urine. One of the two curry pots was poisoned during the cooking for the preparation of the festival in a small town in Wakayama city. Wakayama is a city near the Osaka Kansai International Airport. Although the outline was reported by Kimura [1], a brief chronologically ordered outline should be described here.

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The curry was cooked in two pots in a garage of a festival organizer's house. The curry was cooked from noon till 3 pm there, and then moved to the festival venue. During the noon and 3 pm, the curry pots were kept boiling by housewives of the organizers in turn. One of the housewives there, Mrs. H, was arrested on October 4 and prosecuted as the murder on December 29. She was sentenced to death on December 11, 2001, at the Local Court of Wa‐ kayama. Then again she was sentenced to death at Osaka Court of Appeal. Finally, May 18, 2009, the death penalty has been fixed at the Supreme Court of Japan. She has denied from the first until now, but she is now in the death row.

The only evidence was a paper cup found near the cooking site. This paper cup might have been used to poison the curry pot bringing arsenic. Powder of about 35 mg arsenic oxide, As2O3, was left inside of the paper cup. Her husband had arsenic oxide powders as white ant pesticide, as his job was white ant exterminator. Therefore the key forensic analysis was the identification of arsenic oxide powders between her husband's and the powder adsorbed on the inner surface of the paper cup. "High concentration arsenic" was found on one of her hairs, which was one of the several hundreds of hairs cut on December 9, 1998, by the police. These two evidences are the main reasons of her death penalty. The hair was analyzed by synchrotron radiation X-ray fluorescence (SR-XRF) and also by atomic absorption spectrometry (AAS). Several impurity elements in the arsenic oxide powders were analyzed by the SR-XRF and inductively-coupled plasma atomic emission spectrometry (ICP-AES), as was reviewed by Kawai [2]. Infrared (IR), ion chromatography/inductively-coupled plasma mass spectrometry (IC/ICP-MS), X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray analysis (SEM–EDX), and many other chemical analysis techniques were used.

Because the chemical poison was used by the Tokyo subway sarin attack in 1995, the Wakaya‐ ma arsenic case attracted large attention by mass media, such as television, newspapers, and gossip magazines, at that time for about 1 year duration. The forensic analyses were performed mainly by the National Research Institute of Police Science, Tokyo University of Science, St. Marianna University School of Medicine, Osaka Electro-Communication University, and Hiroshima University. It was well known to the public at that time that SPring-8, one of the third generation synchrotron radiation facility, a 1.5 km circumference accelerator ring of 8 GeV, was used for the forensic analysis. The forensic analysis of SPring-8 was just 1 year after it became in use. Since 2012, Kawai, the author of the present paper, found many faults in the forensic analyses in this case, of which documents were submitted to the court from the prosecutor, and again this murder case becomes discussed in Japan.
