The baby son of a heavily pregnant Kelly Mary Fauvrelle who was stabbed to death in Thornton Heath has died as detectives released footage of a man seen running away from the house.

The mum-to-be died at the house on Raymead Avenue on Saturday  but her baby was delivered by paramedics at the scene and was initially taken to hospital in a critical condition but died in the early hours of Wednesday, the Metropolitan Police said.

This new CCTV released by police shows a man walking towards Ms Fauvrelle’s address at around 3.15am.

Click here to see the footage

Just over 10 minutes later, the same male can be seen running back along Raymead Avenue, away from Kelly Mary’s address, toward Colliers Water Lane.

The boy was named Riley by Ms Fauvrelle’s family and had been chosen by Kelly Mary. This heartbreaking pictures taken back in April show Kelly Mary celebrating her pregnancy. Kelly Mary posed with a message to her son on a cake with blue balloons with the message “It’s a Boy” and a cake with the words “See you soon Riley”.

Detective Chief Inspector Mick Norman, who is leading the investigation, said: “The release of this footage is the next step in what has been a fast-paced, and extremely challenging investigation.

“We need to identify the man shown in the footage urgently, even if only to eliminate him from our enquiries. I need to hear from anyone who knows who he is. If this is you, it is imperative that you contact my team immediately.”

He added that the force was unable to say whether Ms Fauvrelle’s attacker was known to her and officers are keeping an open mind.

Mr Norman said: “A dedicated team of detectives are working day and night on this investigation.

“We have assured Kelly’s family – and I want to assure local residents and the wider public too – that we are doing absolutely everything in our power to find the person responsible.

“I am aware that there is some speculation about whether Kelly’s attacker was known to her. At this stage we simply are not in a position to say and we must retain an open mind.

“One of the key aims of my investigation is to build a complete picture of Kelly’s life and the people with whom she was in contact, but I also need to consider other possible scenarios.

“Members of the public may have useful information, and I am today reiterating my appeal for anyone who may know anything that will assist the investigation to make contact as soon as possible.”

Kelly Mary’s brother also paid tribute to her on Facebook.

In a post, Stephan Alexander Simpson, said: “Words can’t describe the pain we’re feeling.

“You couldn’t have been a better sister, and I thank you for always being there for me, helping whenever I needed it.

“A beautiful person who’s life has been taken from her. I’ll stay strong, you’ll always be in my thoughts, so please keep watching over us.

“I love you more than you can possibly imagine. Rest in peace Kelly.”

*Two men have been arrested on suspicion of murder.

One, aged 37, was released under investigation on Sunday, and a second, aged 29, has been released on bail until early August.

Anyone with information is asked to call the police incident room on 020 8721 4005 or Crimestoppers anonymously on 0800 555 111.