A Canadian national stabbed a Hong Kong convenience store owner to death while possessed by a demon, a murder trial heard on Tuesday. “You’re gonna die, I swear,” Bui Van-cuong purportedly shouted, moments before he allegedly stabbed Cheng Ka-pui in the chest at his franchised 7-Eleven store in Yau Ma Tei in March last year. Lawyers said Bui attacked Cheng with such savagery that the knife broke in two. The force was so great the blade broke from the handle Prosecutor Phil Chau “The force was so great the blade broke from the handle,” prosecutor Phil Chau told the High Court jury in his opening address. Bui told police he was affected by a demon who told him to stab Cheng, the prosecutor added. Bui, 32, of Vietnamese descent, pleaded not guilty to murder. Chau said Bui went into Cheng’s Pitt Street shop three times on March 8. On the second occasion he made off with potato chips without paying for them, then opened the packet and began eating them, prompting a row between the men. The prosecutor said Bui returned to the store a third time, this time carrying a knife he had stolen from a Wellcome supermarket. “He slammed the knife on the cashier desk … He went around the cashier desk and confronted the deceased,” Chau said. “I do not want to die,” Cheng was heard to say in reply to Bui’s threats. But the defendant then stabbed Cheng once in the chest, Chau said. Closed-circuit television footage played in court showed Cheng had begun to fight back and stayed on his feet for a few seconds before collapsing to the floor, with blood gushing from a 2cm wound. He was comforted by a woman, who told him to “hang in there”, while a man took off his T-shirt to put it over Cheng and someone called police. The prosecutor said Bui went back to a supermarket nearby to steal a bigger knife and was arrested the next day. Cheng was taken to Kwong Wah Hospital, then transferred to Queen Elizabeth Hospital, where he died on March 14. A postmortem examination report showed he had suffered a heart injury that caused massive blood loss. Chau said that Bui told police Cheng had beaten him so he had stolen the knife to scare him. He did not want to kill him, he claimed, but was affected by the demon. He also told police he was not under the influence of alcohol or suffering any mental condition. The trial continues on Wednesday before Madam Justice Maggie Poon Man-kay.