She said Tsang told her about the killing, but in a jokey way, meaning she did not take it seriously. She only realised there really was a dead body in her home when she saw Tsang and the two others moving the block of cement through a room of towels drenched in blood, she told the High Court.

Tsang and the deceased used to have a business together. When the victim went to the house that day he intended to pick up a cashier’s order for HK$5 million (US$640,000), a sum he wanted in return for withdrawing from the business arrangement, prosecutors said. They alleged one of the men attacked the deceased, also known as “Ah J”, with chloroform, before they injected him with alcohol and hid the body in a slab of cement. All three have pleaded guilty to one count of preventing the lawful burial of a body.
Ho said on Thursday Tsang told her not to call police after the killing, but she dared not ask why. 

“I thought that if I appeared to do anything unusual then they would kill me too,” she said, during emotional testimony.

“I knew what happened. I was very frightened they would also kill my boyfriend.”

Ho, granted immunity from prosecution in return for her testimony, recalled that on the day of the alleged crime she saw Lau holding a pair of women’s underwear soaked in chloroform near the stairs, while she slept on the flat’s mezzanine floor. She said after that she heard a commotion downstairs, followed by muffled words as though someone’s mouth had been covered. She said Tsang later came up to look for a syringe, which he used to draw something from a bottle. 

After that, she went on, she heard someone say they did not know “if he’s really dead or pretending to have been knocked out”. 

Then Tsang told her “Ah J was dead”, jokingly. He told her they had put the body on a laundry rack in the bathroom downstairs, but she did not believe him and did not check.

“At that time I felt very shocked and I did not know how to respond,” she said. So she went back to sleep. But while she was in bed, she heard the three talk about disposing of the body in a rubbish bag or a wardrobe, she said.

On March 5, she said, she got home to find a block of concrete in the middle of the living room, with sand scattered on it. The room was cold, which Tsang told her was necessary for the cement to dry. 

She woke up the next day to the sound of “stone grinding and scratching” from downstairs, accompanied by “a little smell of blood”. She started to believe “a little bit” that Cheung Man-li had indeed died, as Tsang told her they were dealing with the cement block and had dumped his property.

On March 7, she saw the trio moving the block as blood dripped from it. 

“There were a lot of towels soaked with thin blood on the floor,” she said, adding she used an air-freshener to get rid of the smell.

Later, as she and the men talked, Ho told court, Lau said they might have to go on the run if they could not figure out a way to get away with the killing. Tsang, she said, told her not to call police.

She got a call when she was out the following day from Cheung, saying that they could not move the slab, which had set off the alarm in the lift. The men tried to take the body out of the cement, but ended up breaking its arm, she was told.

Ho said the trio then asked her to flee to Taiwan with them, Tsang telling her that if she refused to go then his uncle, a senior police officer, could blame it all on her. Tsang also had her passport. So, she told the court, she followed reluctantly. 

But while there, she said, she managed to contact her boyfriend, who came to retrieve her and reported the matter to Taiwanese police.

When she returned, she was arrested in Hong Kong.

The trial was scheduled to continue before Mr Justice Patrick Li Hon-leung on Friday.