The arrest comes two days after detectives found the car of a taxi driver they were seeking in connection with the murders which were discovered on Sunday.
Police are still seeking the car's owner, 36-year-old Rahan Arshad, after discovering the bodies of the woman, two young boys and a girl at a house in Cheadle Hulme.
Arshad, who has not been seen for four weeks, was the husband and father of the deceased who were Uzma Rahan, 32, Adam, 11, Abbas, 8, and Henne, 6.
Post mortems on the children showed they all died as a result of serious head injuries. The fourth post mortem is expected to be carried out later on today.
Officers discovered the bodies in the house after being called by concerned neighbours who . . . .