A 36-year-old man has been arrested on suspicion of the murders of his wife and their three children.
Mr Arshad was arrested at Heathrow Airport
The bodies of Uzma Rahan and her two sons and a daughter were found at their home on Turves Road in Cheadle Hulme, Greater Manchester, on 20 August.
Rahan Arshad was arrested at Heathrow Airport after getting off an incoming flight from Bangkok, Thailand.
Greater Manchester Police said he would be brought to Manchester for questioning later.
Mrs Rahan and her three children Adam, 11, Abbas, eight, and Henna, six, had all died from head injuries, post-mortem examinations revealed.
Police believe their bodies could have been in the house for up to four weeks.
Earlier this month, murder squad detectives arrested a 40-year-old man and a 35-year-old woman in connection with the killings. They were later released on police bail.
Uzma Rahan and her three children were found dead in the house
Det Supt Martin Bottomley, of Greater Manchester Police, said the family had lived in the house for about 18 months.
Mrs Rahan was from Pakistan but her husband is British-born.
Police knew Mr Arshad had left the UK on a flight bound for Thailand about four weeks ago.
His silver BMW 320 sports car was found abandoned at a Heathrow Airport Terminal 3 car park.
Greater Manchester Police had been liaising with Thai police since his car was found on 21 August.
He was detained at the Padang Basar checkpoint in southern Thailand, on the border with Malaysia, while attempting to renew his visa to remain in the country.