An autopsy will be carried out later on Wednesday to establish whether foul play was involved in the death of a 52-year-old man.
The man, surnamed Fong, was found lying unconscious in the bathroom of his ground-floor apartment on Tai Hang Road at about 8.45am on Sunday. He was declared dead at Ruttonjee Hospital in Wan Chai.
Police said on Sunday that an initial investigation found nothing suspicious, but detectives have since launched a homicide investigation after pathologist found a strangulation mark on his neck on Tuesday.
On Tuesday night, two domestic helpers, aged 40 and 70, were picked up from the apartment. They are being held for questioning at Wan Chai police station.
Police said an autopsy would be carried out on Wednesday.
Fong’s mother, 88, lives in a first-floor flat in the same building. The two helpers are hired to look after her and her son, who has Down's syndrome.
[Correction: An earlier version gave the wrong age for one of the domestic helpers as 47. One of the helpers is 70 years old.]