London police detectives say the fact that Dr Imran Farooq was about to launch an independent political career before his murder remains a key line of inquiry in the probe.
The former Muttahida Qaumi Movement (MQM) leader was stabbed to death on September 16, 2010 outside his home in Green Lane, Edgware while he was on his way home from work.
In a statement issued Monday, the London Metropolitan Police said their Counter Terrorism Command unit has so far spoken to 4,076 people, reviewed 6,350 documents and followed up 2,114 lines of inquiry in order to bring the killers of Dr Imran Farooq to justice.
“This remains an ongoing investigation with a number of lines of inquiry being actively pursued. It is thought that his murder would have required careful planning and help from other people, some of whom may have provided assistance or information unwittingly,” said the statement.
“Police know that in July 2010, Dr Farooq set up a Facebook profile and amassed a large number of contacts through this social network. However, we retain an open mind as to his murder,” it added.
On 24 June this year, police had arrested a 52-year-old man on suspicion of conspiracy to murder at Heathrow after landing at the airport on a flight from Canada. However, he was later released under bail at a date later in September.
In the statement, the London Met Police appealed for anyone with information leading to the identification, arrest and prosecution of those responsible for the murder.