Video report by ITV News Correspondent Rebecca Barry
The baby son of a mother-to-be who was stabbed to death has died.
Named Riley, he was delivered by paramedics at the scene of the attack but died in hospital in the early hours of Wednesday.
Riley’s father, who did not live with his mother, Kelly Mary Fauvrelle, was with his son at the time of his death and is not currently not a suspect said detectives who are treating this case as a double murder investigation.
Riley's mother, Ms Fauvrelle, a Royal Mail worker, was found with stab injuries at her home in Croydon in the early hours of Saturday.
Ms Fauvrelle's entire family – her mother, two brothers, sister and sister’s baby son – were all also in the property.
They were alerted to the “vicious” attack by her screams at around 3.30am. The 26-year-old died at the scene.
The news comes as police released CCTV of a man they wish to identify who was walking towards Ms Fauvrelle's address, and running away from the scene minutes later.
In the footage released by the Metropolitan Police, a man is seen walking towards the property in Raymead Avenue, Thornton Heath at 3.11am and running back just over 10 minutes later.
Detective Chief Inspector Mick Norman of the Met’s Homicide and Major Crime Command told ITV News the police are treating this case as a double murder investigation and are appealing for information, “however trivial it may seem”, to give officers “as complete a picture of Kelly as possible”.
Police are keeping an open mind around the motive and circumstances of the attack, he said, and understand Ms Fauvrelle was alone in her bedroom when she was stabbed.
DCI Norman said Ms Fauvrelle had her own bedroom on the ground floor at the rear of the premises.
He said: ''In terms of access there is a communal passageway and potentially the obvious access point would be through the kitchen.
“There is no sign of a forced entry but that does not mean, through accident, the premises were insecure.”
He added the murder weapon, which could be a kitchen knife, is yet to be found.
“From our initial crime scene investigation and initial work it would appear the attack has happened within her bedroom,” he said.
“Kelly was a popular girl, she worked and was working up to the point of her murder. She was a very private person so part of what I’m appealing for people who know her, her friends.
“We need to build up as complete a picture of Kelly as we possibly can.”
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.
As part of the appeal released with the CCTV footage, DCI Norman 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 the force was unable to say whether Ms Fauvrelle’s attacker was known to her and officers are keeping an open mind.
DCI Norman continued: “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.”
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 555111