Dr Farooq, 50, was repeatedly stabbed in the head and neck during the assault in Edgware, north London.
He was a leading member of the Muttahida Quami Movement (MQM) party, which is one of the largest in Pakistan.
There were suggestions from Pakistan that he may have known his killer. When police arrived at the scene, they found Dr Farooq’s body outside his house.
The politician claimed asylum in Britain after spending seven years on the run as one of Pakistan’s most wanted fugitives. He was accused of a range of charges, including murder and torture.
He has not returned to Pakistan since his arrival in England in 1992.
He claimed that year that he was wanted “dead or alive”.