A police officer made degrading and sexist insults about two murdered women as he shared photos from the scene where they were found with a colleague photographing their bodies and also sharing the images via WhatsApp.

The two Metropolitan police officers pleaded guilty on Tuesday after sharing photographs from the crime scene they were supposed to be guarding in a London park, where two sisters, Nicole Smallman, 27, and Bibaa Henry, 46, were found stabbed to death.

PC Deniz Jaffer, 48, and PC Jamie Lewis, 33, admitted misconduct in public office at the Old Bailey, with the judge, Mark Lucraft QC, warning that they were “extremely likely” to be jailed.

Jaffer left the post he had been assigned to in June 2020 at Fryent Country Park in Wembley, north-west London, and went into bushes where the women had been left by their satanist-obsessed killer. The officer took out a mobile phone and took pictures of the bodies.

He sent four images to Lewis, who edited one of the photos and superimposed his face on to it with the two murdered women visible in the background. Lewis took other photos from the crime scene, which did not show the victims, and shared them with a group of more than 40 officers via WhatsApp who called themselves the “A-team”.

The Independent Office for Police Conduct said Lewis had “used degrading and sexist language to describe the victims”. A spokesperson confirmed the remarks were directed at the murder victims and it was fair to characterise the remarks as insulting.

Henry, a senior social worker, and Smallman, a photographer, had been celebrating the elder sister’s birthday in the park. After the celebration ended, they stayed behind and were attacked. They were reported missing the next day and a search by family and friends led to the partner of one of the sisters finding their bodies.

The family of the murdered women were last week backed by the police watchdog in their claims the Met had let them down when the force failed to search for the two sisters after they went missing.

The scandal, first revealed by the Guardian, has further blighted the Met’s reputation and the guilty pleas meant more detail about the officers’s actions were finally revealed.

On Tuesday, the women’s mother, Mina Smallman, said the Met was “beyond hope” and called for its leaders to “get the rot out once and for all”. She accused the Met commissioner, Cressida Dick, of a “shoddy way of behaving”. She said: “She has not contacted us to say ‘I am really sorry’. She has not spoken into this story at all. And it’s shameful that the IOPC [Independent Office for Police Conduct] had to tell the Met they should apologise to us in their failings for the missing persons [investigation]. Too little, too late. Too little, too late.

“When I was in a senior position, if my organisation or department failed, it was on me. I had to take the can for it. Well, it’s now time for them to take the can for it. They are beyond hope.”

The Guardian understands that Jaffer was a mentor for new recruits. The Met say he resigned in August and that he and Lewis will face a fast-track process to sack them.

Jaffer, of Hornchurch in east London, and Lewis, from Colchester in Essex, were based with the Met’s North East Area Command.

The judge told the men he viewed their offences as grave enough to merit lengthy imprisonment: “These matters are extremely serious and you should be under no illusions when you return for sentence it is extremely likely you will receive custodial sentences, custodial sentences of some length for your conduct.”

The indictment says the offences took place between 7 June, the day the bodies were found, and 23 June 2020.

In a statement after the guilty pleas, the Crown Prosecution Service said: “PC Lewis edited one of the pictures by superimposing his own face on to the photograph with the victims in the background. He sent the resulting image to PC Jaffer, who then forwarded it unsolicited to a female officer also present at the scene.

“PC Jaffer showed one of the photos of the victims to a male officer as they left the park. PC Lewis also shared photographs he had taken at the crime scene, which did not show the victims, with a WhatsApp group of 40-plus police officers called the A Team.

“PC Jaffer, meanwhile, sent photographs of the victims to three friends via WhatsApp.”

Dick said: “I deeply regret that at a time when they were grieving the loss of their loved ones who were taken in such awful circumstances, they faced additional distress caused by the actions of two police officers. What former PC Jaffer and PC Lewis chose to do that day was utterly unprofessional, disrespectful and deeply insensitive.”

The officers will be sentenced at a later date and were granted bail.

Danyal Hussein, who was 18 at the time, from Blackheath in south London, has been convicted of the murder of both sisters and jailed for life.

The IOPC said that three officers who received the images but did not report them had a case to answer for misconduct.