Detectives yesterday named the mother and three children found murdered in their home.
The bodies of Uzma Rahan, aged 32, and her children, Adam, 11, Abbas, eight, and Henne, six, were discovered by police on Sunday evening.
They may have been killed up to four weeks ago and police are anxious to trace Mrs Rahan's husband Rahan Arshad who vanished at the same time.
The taxi driver's car, a silver BMW 320 Diesel M sports car, was discovered at Heathrow Airport on Monday night and there are fears he may have fled the country.
The grim discovery was made shortly after 5.05pm on Sunday when officers were called to the house in Turves Road, Cheadle Hulme, near Stockport.
A spokeswoman for Greater Manchester Police said: "The car belonging to the missing occupant of a house in Cheadle Hulme has been found in a car park at Heathrow Airport.
"Officers are still trying to trace Rahan Arshad, aged 36, of Turves Road in Cheadle Hulme, who has not been seen for weeks. He is believed to be the husband and father of the deceased.
"The car appears to have been parked at the airport several weeks. Police are making enquiries with the airport and airlines to establish if Rahan has travelled recently."
Officers launched an international manhunt.
The bodies were removed late on Monday as forensic experts continued a fingertip search.
Not all the victims were in the same room, but detectives would not be drawn on locations or a possible murder weapon.
Police had been called last Friday but when officers arrived there was no "immediate concern". A neighbour is believed to have contacted the police t wo days later after knocking on the door and getting no reply but noticing a "stomach-churning" smell.
Detective Superintendent Martin Bottomley is leading the murder hunt for Arshad.