Imran Farooq murder: Police spoke to 4,000 people
Officers investigating the murder of Pakistani politician Dr Imran Farooq have spoken to more than 4,000 people in the three years since his killing.
The 50-year-old was attacked outside his home in Green Lane, Edgware, on 16 September 2010. He died from stab wounds and blunt trauma to the head.
Two people were arrested by police over the killing of the senior leader of the MQM party but no-one has been charged.
Police said they have followed up 2,114 lines of inquiry in the case.
A kitchen knife and a brick used in the attack were recovered from the scene, police said.
Detectives from the Metropolitan Police Counter Terrorism Command (SO15) have also reviewed 6,350 documents in relation to the case and a reward of £20,000 for information that may lead to the killer being caught is being offered.
Appealing for information, the Met said: "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.
"Detectives believe that Dr Farooq was about to launch a new independent political career before his death and this remains a key line of inquiry in this investigation."