Prosecutors in Osaka have indicted a man for murdering a female acquaintance with thallium, which was used as rat poison.
A report by the BBC said Kazuki Miyamoto, 37, is accused of killing 21-year-old university student Hinako Hamano last October by lacing her drink with thallium.
Thallium is a soft metal which dissolves in water and has no taste or smell- making it hard to detect outside a laboratory setting.
Just 1g of it could kill an adult.
Thallium was also recently found in his female relative, who has been in a coma since 2020, local media reported citing sources.
According to the report, the suspect was arrested on 3 March in Kyoto.
But police have not found a motive, nor how he had laid hands on the poison.
Mr Miyamoto, a real estate agent, is believed to have administered thallium to Ms Hamano sometime around 11 and 12 October when he visited her flat in Kyoto.
He had told police the two were dining out on the night of 11 October before heading to Ms Hamano’s home for drinks, the Japan Times said, citing investigators.
According to Mr Miyamoto, Ms Hamano experienced severe coughing fits.
He then contacted her family, who took her to a hospital the next day.
Hamano died on 15 October of severe respiratory failure – thallium was found in her vomit and urine, the Asahi Shimbun reported.
Writing by Abdullahi Lamino; Editing by Julian Osamoto