Nearly a week on from the murder of two sisters in a Wembley park, police say Nicole Smallman, 27 and Bibaa Henry, 46 were killed by a stranger.
The sisters were stabbed to death in Fryent Country Park in Wembley, north-west London.
They had been celebrating Bibaa's 46th birthday with friends and family.
Officers have been handing out leaflets and engaging with members of the public in the hope of gathering further information about the killing.
Police said they are confident that Nicole and Bibaa were murdered by someone who they did not know.
Officers are currently trawling through hundreds of thousands of tonnes of rubbish from a local refuse depot in search of any items relevant to the murder investigation.
Police are asking the public for their help in finding Nicole and Bibaa's killer.
The police believe the suspect left the park via the Valley Drive entrance.
An extensive crime scene still remains in the park.
Police said a number of people have come forward with information, but they still need to hear from anyone who was in Fryent Country Park the evening of Friday 5 June or early into Saturday 6 June.
Extra resources have been brought in to help the investigation from across the Metropolitan Police, including additional detectives.
A 36-year-old man arrested in south London on suspicion of murder was released with no further action.
Anyone with information is asked to call 101.