A missing car, thought to have been taken by a man suspected of the murder of a family of four, is the focus of a renewed appeal by police.
Anxiang Du, 52, is wanted in connection with the deaths of university lecturer Jifeng Ding, his wife Helen and their two daughters, who were found stabbed to death at their home in Northampton last weekend.
A re-trace of the route businessman Du, who lived in Coventry and worked at a herbal medicine shop in Birmingham, is believed to have taken prompted several witnesses to come forward.
But police said a missing silver five door Vauxhall Corsa is the focus of a renewed appeal by officers investigating the murder.
Northamptonshire Police said despite a number of appeals, including showcasing an identical Corsa with the same registration number BG60 PMO, and a retrace of the route believed to have taken by Mr Du on that Friday, there had been few witnesses to the vehicle come forward.
Detective Superintendent Glyn Timmins said: "Unfortunately the car is still missing.
"Being able to locate the car would provide us with a vital step in trying to trace the steps taken by Mr Du and possibly even find him as well. Finding the car is a key priority.
"The lack of ANPR (Automatic Number Plate Recognition) hits made on the vehicle is still puzzling for the major investigation team.
"However, through this re-appeal I am keen to focus in particular at anyone who works within public car parks, owns or runs car parks, anyone who issues tickets or is involved in towing away cars.
"Although it is impossible to say where the car currently is, there is a strong possibility that it has been abandoned in a car park somewhere not making it immediately identifiable to people."