Five years on from the brutal murder of an exiled Pakistani politician in London, police said they remain committed to finding the people behind the attack.
Dr Imran Farooq, 50, was stabbed several times and bludgeoned with a house brick on his way home from work.
No-one has been convicted of his murder in Edgware, north London, on September 16 2010, but two Pakistani men have been named as being wanted in connection with the killing.
Moshin Ali Syed, 30, and Muhammad Kashif Khan Kamran, 36, were both in the UK for some time up to that date, police said.
The investigation has so far seen detectives speak to 4,555 people, review 7,697 documents, follow up 2,423 lines of inquiry and seize 4,325 exhibits.
Three men arrested in connection with the investigation at various points over the past five years were all released without charge.
Scotland Yard said: "Detectives from the Met Police Counter Terrorism Command (SO15) are investigating Dr Farooq's murder and remain committed to finding those responsible."
Police said they have been in regular contact with authorities in Pakistan during the investigation.
Dr Farooq was a prominent member of the Pakistani political party MQM (Muttahida Qaumi Movement) and had been living in exile in the UK for more than a decade when he died.
In the weeks before his death, Dr Farooq had been trying to raise his own political profile and had set up a Facebook page, which police have previously said forms a "key line of inquiry" .