Detectives today named the mother and her three children found dead in their own home.
The bodies of Uzma Rehan, 32, and her children, Adam, 11, Abbas, 8, and Henna, 6, were discovered by police on Sunday evening.
The victims may have been killed up to four weeks ago and police are anxious to trace Mrs Rehan's husband Rahan Arshad who vanished at around the same time.
The taxi driver's car, a silver BMW 320 Diesel M sports car, was discovered at Heathrow Airport at around 9pm last night and there are fears he may have already fled the country.
Police said a formal identification of the victims had not yet taken place.
The cause of death has not yet been established and post-mortem examinations of the bodies are due to be carried out later today.
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, 36, of Turves Road in Cheadle Hulme, who has not been seen for several weeks.
"He is believed to be the husband and father of the deceased.
"Formal identification of the bodies has not been carried out yet but they are believed to be the residents of the house, Uzma Rehan, age 32, and her three children, Adam, age 11, Abbas, age eight, and Henna, age six.
"The car appears to have been parked at the airport for several weeks.
"Police are currently making enquiries with the airport and airlines to establish if Rahan has travelled from the airport recently."
Officers yesterday launched an international manhunt for Mr Arshad and every police force was put on alert.
The bodies were removed from the house late last night as forensic experts continued a fingertip search of the murder scene.
Not all the victims were found in the same room, but detectives would not be drawn on their locations and a possible murder weapon.
Police had been called to the house last Friday but when officers arrived there was no "immediate concern" for the safety of the family.
A neighbour is believed to have contacted the police two days later after knocking on the door and getting no reply but noticing a "stomach-churning" smell coming from the house.
Detective Superintendent Martin Bottomley, who is leading the murder hunt, said the family had lived in the house for around 18-months and the young children were all pupils at a local primary school.
He refused to comment on whether the couple had been experiencing marital problems.
Mrs Uzma Rehan was from Pakistan while her husband is British born.
Mr Bottomley added officers were in contact with members of both families, but had not yet spoken directly to relatives in Pakistan.
He refused to be drawn on suggestions that "extreme violence" had been used in the murder.
He said the post-mortem examinations were ongoing due to the state of the bodies and may continue into tomorrow.
Mr Arshad's BMW was found at Heathrow's terminal three.