Armed robbers who attacked a former police officer "probably played a role in her death", an inquest found.
Hang Yin Leung died 11 days after she fell ill at a police station after giving a statement.
The 64-year-old told police masked men had burst into her home in January 2017 and threatened her with an ice pick before she chased them off.
The inquest in Milton Keynes concluded the raid may have been linked to a heart attack which killed Mrs Leung.
The gang stole jewellery, cash and her Hong Kong police medal but, despite a TV appeal, nobody has ever been charged.
Assistant coroner Adam Smith said: "She had been admitted to the hospital on 1 February 2017 having become unwell when giving a statement to the police about an assault she had suffered during a burglary the previous day.
"It is probable that the assault played a role in her death."
Her husband Chun Yau, with whom she ran the Jade Gardens Chinese takeaway in Walnut Tree, Milton Keynes, said the burglars had "no humanity".
THAMES VALLEY POLICE
Det Con Jenny Chapman told the hearing a murder case had been "filed" without anyone being charged as there was no forensic evidence available to identify the attackers.
There have been four arrests but no charges in the case, which appeared on Channel 4 documentary Catching A Killer in May 2018.
In a statement before her death, Mrs Leung told officers: "Male one pushed me down to the floor of the lounge and used an ice pick to threaten me.
"I struggled and he used his hand to hit me three to four times to the back of my head."
Her son Keith Leung said she was a "very strong woman who had been through a lot in her life".
