Police in Sydney were Tuesday trying to work out what happened to a mystery Asian man who hammered on the door of an elderly couple's house naked and covered in blood, pleading for help.
The man, who does not speak English, staggered to the home on Monday night with significant head injuries before collapsing on the doorstep.
"I was shaking like a leaf," an elderly woman who lives at the home and did not want to be identified, told the Sydney Morning Herald.
"But we couldn't just leave him there to die."
Reports said he told police through a Mandarin interpreter that he was mugged, stripped, tied up and locked in a car boot before being dumped.
Detective Inspector Danny Doherty said the victim had no identification with him and his identity was as yet unknown.
"All we know is it's a man of Asian descent and that he is in his early 20s," Doherty told reporters, adding that they were not ruling out an abduction.
"There will be people in the community who know exactly what happened," he added.
The man is in a stable condition in hospital and police are waiting to formally interview him.