Police arrested a Kyoto resident on Wednesday on suspicion of attempted murder for allegedly poisoning his aunt with thallium in a financially motivated crime in 2020.
Kazuki Miyamoto, 37, is already under indictment for the murder by poisoning last year of Hinako Hamano. The 21-year-old Ritsumeikan University student died after ingesting thallium, a highly toxic substance once widely used in rat poison.
Miyamoto's 61-year-old aunt was hospitalized due to the alleged poisoning in mid-July 2020 and remains unconscious, the Osaka prefectural police said.
Following her incapacitation, he became the head of a real estate firm she owned in October of the same year.
According to the police, Miyamoto's aunt began complaining of stomach pain in July 2020. Tests of her urine and blood serum showed traces of thallium.
The suspect has remained quiet over the allegation of poisoning his aunt, the police said.
Miyamoto stepped down from his post at the firm after he was arrested and indicted in March this year over the alleged murder of Hamano.
According to the indictment in the case of Hamano, then a third-year student at the private university in Kyoto, Miyamoto got her to ingest the toxic substance while at her home in Kyoto around Oct. 12.
The thallium poisoning caused her to die of acute respiratory distress syndrome, which prevents the lungs from providing sufficient oxygen to vital organs.
The police said lethal amounts of thallium were found in her vomit and urine.