**2. Influence on the academic researches of Wakayama arsenic murder case**

The sarin attack at Tokyo subway was just a few years before this arsenic murder case. Therefore, many academic research papers on Wakayama murder case were published, which discussed the relation of the subway sarin attack. Some examples of papers related to the Wakayama case are as follows.

From the point of view of medical treatment at disasters, such as Matsumoto sarin attack in 1994, Tokyo subway sarin attack in 1995, Wakayama arsenic murder case in 1998, and other bombing terrorism in Japan from 1990 to 2002, were compared and discussed a future risk of terrorism and emergency management [3]. However this kind of lessons were not used at the earthquake, tsunami, and nuclear disaster at March 11, 2011, Japan. Intoxication with arsenic curry was reported in the same journal [4]. Bioterrorism threats to food were discussed [5]. Related to the subway sarin attack, importance of information sharing systems among hospitals was discussed [6], because the victims were distributed to many hospitals in Wakayama city. The patients were first treated as taking rotten food, then organophosphorus pesticide or cyanide. Therefore the information sharing was important. "FACT-Graph", a data analysis method, was used to analyze keywords "cyanide" and "arsenic" as nodes of the graph analysis [7]. PTSD (posttraumatic stress disorder) was discussed [8]. Copycat poisoning cases, such as sodium azide (NaN3) and cyanide incidents in 1998, were discussed from the view point of chemical disaster response system [9]. A vast number of copycats appeared just after the Wakayama incidence. The importance of quality assurance against incidents of unwanted chemicals in food such as arsenic, cadmium, mercury, and lead, including Wakayama case, were systematically discussed [10]. Case seen in clinical practice at intentional acts such as nicotine, arsenic (Wakayama), rat poison, and methamidophos were discussed [11]. Economic impact of arsenic contamination in Bangladesh was studied referring to the Wakayama incidence [12].

Concerning medical treatment, dermatology [13–16], neurology [17], and many other papers were published.

Between the Wakayama incident on July 25, 1998, and the accusation of the suspect on December 29, 1998, many copycats were appeared mimicking poisoning [18], as mentioned above, using different chemicals, such as sodium azide, pesticides, and cyanide. At the first stage of Wakayama case, cyanide was erroneously detected, and this point was studied from the view point of chemical analysis [19–21].

Related to analytical chemistry, ICP-AES analysis of impurity elements of arsenous oxide in order to identify the As2O3 in paper cup and that of Mrs. H's husband were reported by researchers of National Research Institute of Police Science, Japan [22–24]. Forensic analysis using SR-XRF analysis was reported [25–29]. The importance of SR-XRF for forensic analysis was also reported in an encyclopedia [30]. LC/MS [31] and HPLC/ICP-MS [32] were reported as arsenic chemical state analysis methods related to Wakayama case. A screening method of inorganic arsenic in urine was developed [33]. A large number of other papers can be found at Google Scholar by the key words, "Wakayama arsenic".
