A murder investigation has been launched after two sisters were found dead in a park following a birthday party.

Police are treating the deaths of Nicole Smallman, 27, and Bibaa Henry, 46, as “suspicious” after they were found in Fryent Country Park, in Wembley, north-west London, on Sunday afternoon.

Detectives believe they were among a group of around 10 people who gathered in a spot, which is popular for its views over London, from 7pm on Friday to celebrate Ms Henry’s birthday.

They are thought to have been left alone together as others left throughout the evening, and were reported missing to police on Saturday when they did not return home.

Police were called shortly after 1pm on Sunday to find the sisters unresponsive and they were pronounced dead at the scene.

The families of Ms Smallman, from Harrow and Ms Henry, who lived in Brent, have been told.

Detectives are treating their deaths as suspicious and a murder investigation has been launched.

Detective Chief Inspector Simon Harding said: “We are in the very early stages of the investigation and are working hard to find out what led to these two women losing their lives.

“Their families have been devastated by their loss and they need answers.

“They have asked that their privacy is respected at this time as they come to terms with this horrific incident.

“I need to hear from anyone who was in Fryent Country Park on the evening of Friday June 5 or early into Saturday June 6.

“The area the group were situated in is around a five-minute walk from the Valley Drive entrance of the park, leading to a hill area.

“The area the group were in would be a well-known spot to sit and look over London.

“If you were in that area of the park from the evening of June 5 through to Sunday lunchtime, noticed the group, or saw anything else suspicions, please contact us immediately.

“You may have stumbled upon items of property, but not realised the significance of them. If you did, you may well have information that could assist us hugely.

“No matter how insignificant it may seem, please contact us via the incident room on 0208 721 4205, or via 101.”

An extensive crime scene remains in the park as investigators search for clues but there have been no arrests.

North West Borough Commander Roy Smith, added: “This is an awful incident and our thoughts are with the victims and their family.

“We are working closely with the investigation team to ensure we get answers to what has happened. Local officers will be conducting reassurance patrols and will be happy to speak to any concerned residents.”