Police raided a series of properties yesterday in an attempt to track down the killer of a pregnant woman who was murdered at her home after a long-running dispute with her neighbour.

A postmortem last night showed that Krystal Hart, 22, died from two gunshot wounds to the head after being shot at close range in her flat in Battersea, southwest London.

Detectives believe her killer, a white man aged between 30 and 50, is a friend of Hart’s downstairs neighbour with whom she had clashed over matters thought to include loud noise and parking. Relations had deteriorated to such an extent that Hart’s stepfather had installed CCTV cameras inside and outside the flat, with court action reportedly pending.

Friends and relatives paid tribute to the mother-to-be, a former receptionist at the department of John Prescott, the deputy prime minister. She was six weeks pregnant.

Carol Chalk, Hart’s great-aunt, left a bouquet of roses at the murder scene. A card read: “To Krystal, a very special young lady. Why would anybody want to do this to you?

“You had all your life in front of you and your baby. You are a beautiful girl, I will never forget you. Your lovely face will always be in my heart.”

Hart was murdered at about 11am on Good Friday in an affluent neighbourhood of the capital dubbed Nappy Valley because of the large number of professional couples living there with young families. She lived with her mother in a top-floor Victorian flat owned by the Family Mosaic housing association, one of the largest housing groups in the country.

An hour before Hart was shot, her boyfriend David Siveter reportedly got into an argument with a man visiting Angela Brewer, Hart’s neighbour in the downstairs flat on Belleville Road.

The two men left but the suspected killer, who was delivering an Easter egg to Brewer, returned 30 minutes later and demanded to see Hart’s boyfriend, shouting: “Where is he?”

He then ran upstairs, kicked down the door to Hart’s flat and fired two shots, killing her instantly.

Neighbours claimed Brewer, who is in her fifties, had regularly been seen arguing with Hart since the young woman moved to the property about a year ago.

Last night police were trawling through CCTV footage from the property to see whether her murder had been captured on film.

Brewer was interviewed by detectives after she dialled 999 following the shooting. She is not being treated as a suspect and is believed to have provided police with the name of her friend, who had been staying nearby with his elderly mother.

The murder weapon, believed to be a handgun, has yet to be recovered.

Detective Chief Inspector Colin Sutton of the Metropolitan police, who is leading the inquiry, said: “While we continue to investigate the possibility that the murder could have been the result of a neighbour dispute, we no longer believe that this was over a parking matter. It seems it was just a very disproportionate escalation of some sort of dispute.”

Police said last night the search for the suspect had been extended beyond the London area although officers believed he was still in the country.

Hart is thought to have lived in the area since she was a child and studied at Battersea Technology College, which she left at 16. Her last job, from which she was made redundant six months ago, involved administrative work at Prescott’s office.

Hart met Siveter, 21, a year ago and the couple were looking forward to starting a family together. A woman answering the intercom at his Wandsworth home last night said: “None of us are up to talking at the moment. David is not coping at all, he is absolutely devastated.”

Hart’s mother, Debbie Penfold, lived at her flat for some of the week, while her half-sister Stella and grandmother Shirley also live in Battersea.

The flat is just yards from the trendy cafes and boutiques of Northcote Road. Celebrity residents believed to live in the area include Jack Davenport, the star of Pirates of the Caribbean, Jack Dee, the comedian and Gordon Ramsay, the chef.

One neighbour said: “I heard noise could have been a problem, but this is more the sort of area where you put a note through the door if someone has had a party and they didn’t warn you.”

Additional reporting: David Langton

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• The real-life adventures of Tintin the spy
• Our universities face a radical upheaval
• Doctor Who