An 18-year-old girl is thought to have made a desperate attempt to call police for help as she and her family were hacked to death in their home.
Xing Ding died alongside her younger sister Alice, 12, and their parents, Jifeng and Helen, at their home in Wootton, Northampton, probably on 29 April, the day of the royal wedding.
It was revealed yesterday that at the time the attack was thought to be taking place, a 999 call was made from the house. The call, probably by Xing, was abandoned and could not be traced but is now being investigated by the Independent Police Complaints Commission. It is understood that the inquiry will focus on the police response to the call.
A spokesman for the IPCC confirmed it is investigating and Northamptonshire Police said a 999 call was made at 3.31pm on Friday, 29 April, but that it would be inappropriate to comment further until the investigation is over.
The prime suspect is Anxiang Du, 52, a businessman with links to the family who left his home on the same day and has disappeared. The last known sighting was on a CCTV tape in London the following morning.