Police in Taiwan say the female friend of an Australian university student is under investigation for poisoning him with a powerful rodent killer, with officers seizing evidence from her Taipei home as the Queensland man was being medically evacuated this week.
Alex Shorey, 24, is slowly recovering in Brisbane's Princess Alexandra Hospital after family and friends raised more than $200,000 to fly him home from Taiwan on Wednesday.
The exchange student had spent a year in Taiwan studying, and was weeks away from returning home to Australia when he started experiencing black skin spots and unusual bleeding.
Doctors at a top Taipei hospital found that he'd ingested superwarfarin, normally used as a rat killer, and his condition critically worsened to include organ damage when his body responded badly to treatment.
A Taipei City Police spokesman told the ABC that investigators on Wednesday "searched the home of a female friend and found relevant evidence".
"Police questioned this female friend on Thursday and restricted her from leaving Taiwan," the spokesman said, confirming she is the only suspect.
Responding to speculation in the media, Taipei City Police also rejected suggestions Mr Shorey may have ingested the rat poison from street food or illicit drugs.
Some Taiwanese media reports have gone further, claiming the suspect is a 45-year-old woman who was Mr Shorey's girlfriend and reporting that rat poison was found at her residence.
One news outlet has published a photo it claims is the suspect emerging from an interview with investigators.
Mr Shorey's father Steve was briefed by Taipei police about the criminal investigation before leaving with his son on Wednesday to fly back to Australia.
He declined to comment further to the ABC while the investigation continued.
The case has captured the attention of Taiwan's media, with multiple medical experts speculating that Mr Shorey would have had to ingest a non-trivial amount of warfarin to exhibit the symptoms he presented with.
Other commentators have honed in on the initial speculation that he may have ingested the rat poison from tainted street food, with a Taiwanese street vendor group angrily rejecting that possibility.