An 18-year-old man has been arrested in south London over the murders of two sisters in a Wembley park. 

The teenager was arrested  overnight on suspicion of the murders of both Nicole Smallman, 27, and Bibaa Henry, 46, at Fryent Country Park in the early hours of June 6.

The pair had met with friends during the evening to celebrate Ms Henry's birthday.

Detective Chief Inspector Simon Harding, who is leading the investigation, said: "This investigation into the awful death of two sisters is of course a priority for the MPS and my officers have been working around the clock to identify the person responsible.

"Given the significance of this development, we visited the family in person today to inform them of the arrest. Our thoughts remain with them at this very difficult time.

"A team of forensic officers have been a constant presence at the park over the last few weeks carrying out meticulous fingertip searches at what is a vast and complex crime scene.

"Whilst that work has now concluded, smaller searches in outer areas of the park will continue.

"To date officers have recovered more than 1,000 exhibits - including property belonging to both Nicole and Bibaa, collected hours of CCTV and visited hundreds of homes and businesses.

"And those inquiries remain ongoing.

"I would continue to appeal to the public to come forward with any information they feel may be relevant to our investigation."

Two police officers have already been arrested on suspicion of misconduct in a public office after claims emerged they had taken "non-official" photographs of the crime scene.

he sisters' mother Mina Smallman told the BBC that the pictures "dehumanised" her children.

"This has taken our grief to another place," she said.

"If ever we needed an example of how toxic it has become, those police officers felt so safe, so untouchable, that they felt they could take photographs of dead black girls and send them on.

"It speaks volumes of the ethos that runs through the Metropolitan Police."

Scotland Yard said its directorate of professional standards was told last week about allegations that "non-official and inappropriate photographs" had been taken at the murder scene.

The sisters are thought to have ended up alone in the park by around 12.30am on June 6, and police said they were in "good spirits" and "taking selfie pictures, listening to music and dancing with fairy lights" until at least 1.13am.

Their last contact with friends and family was about 1.05am, police said.