The family of a murdered woman have hit out at police who failed to investigate her disappearance because she was not considered vulnerable.

Their comments came as brutal sex killer James Flynn was jailed for life for the murder of Charmian Falkner after a Christmas party.

Officers left it to friends of Miss Falkner to break down the door of her killer's bedsit six days after her disappearance. They discovered her corpse lying on his bed.

The harrowing truth can be revealed today as Flynn began his sentence for what the judge called a "horrendous act of mindless violence."

Jurors at Lewes Crown Court who have listened to the full facts of the case took just 40 minutes to unanimously return a guilty verdict today.

Sussex Police has admitted mistakes were made in the early stages of the inquiry and three officers - two inspectors and a sergeant - have been formally disciplined.

Lewes Crown Court heard Miss Falkner, 33, met 34-year-old Flynn at a Christmas party in the Skyline Restaurant, Brighton, on December 21 last year.

The pair, who had both worked at the Brighton Centre, went together to the Queensbury Arms before calling a cab to go back to Flynn's bedsit in Dorset Gardens.

Flynn punched and throttled Miss Falkner when she refused to have sex with him before going to sleep beside her on his bed, the jury was told.

When he awoke to discover she was dead he fled to London.

Miss Falkner's family became concerned when they could not contact her and their phone calls went unanswered.

Family friend Katrina Byrne called the police but was told they did not have the resources to launch a missing persons inquiry.

Finally her family travelled from Devon to search for their daughter.

Miss Falkner's sister Abigail, 32, her partner Laurence Wedge, 49, and Mrs Byrne traced her to Flynn's flat and broke in.

Mr Wedge found Miss Falkner's body wrapped in bloodstained sheets on Flynn's bed.

After the verdict was returned, Judge Richard Brown told Flynn: "This was a horrendous act of mindless violence on your part. Quite why you killed Charmian we will never know. You chose not to say.

"She was obviously a loved member of a family. She had everything to live for."

He said witnesses described Miss Falkner, a former security guard at the Brighton Centre, as a bubbly and lively person who spread joy wherever she went.

He said: "As one witness described her, she was a nice person to know. You have caused inconsolable pain and anguish to her family and friends."

Detective Inspector Malcolm Bacon, in charge of the inquiry, said after the hearing: "Flynn is a cunning, deceitful man shown to be dangerous. He was always going to be a potential threat to women.

"He carried out a callous, cowardly attack for apparently spurned sexual advances.

"His behaviour after the killing of Charmian illustrates this cold and callous attitude and a person for whom life imprisonment was the only sentence."

Flynn had previous convictions for attempted rape in 1989, assault in 1993, harassment of an ex-girlfriend in 2000 and 28 convictions for fraud and theft.

Flynn, also known as Paul, pleaded guilty to manslaughter but denied murder. He told police he was too drunk to remember the killing.

After sentence was passed Miss Falkner's family said they had made an official complaint about the way police handled the case.

Hilary Falkner said: "It was a nightmare. I can't forgive the police for not taking us seriously when a family knew she was missing.

"We were told she was not vulnerable and all the time she was lying there dead. We have launched an official complaint with the Police Complaints Authority.

"This won't bring my daughter back but if it spares another family having to go through this then it will be worth it."

Abigail Falkner said: "Procedures need looking into. My sister may have already been killed, but if the police had looked into the fact she was missing when we first told them I may have been able to see my sister's body and say goodbye."

There have been two internal inquiries into the police's initial inaction. Three officers who were involved have been issued with a written warning.

Detective Chief Inspector Steve Dennis said: "Prior to Charmian's body being found there were some mistakes made in the inquiry.

"Since then our missing persons inquiry system has been reviewed and changed."

He offered a message to the family: "I am extremely sorry. It was a terrible thing for them to discover their daughter had been killed, let alone our inaction at the beginning of the inquiry."

Miss Falkner moved to Brighton when she was 17 to attend Brighton Polytechnic and worked at the Brighton Centre for ten years before leaving the city last year to live with her mother in Devon.

She kept in contact with friends and returned to Brighton on December 16, 2001, to spend Christmas with a former boyfriend, who has since died of cancer.

Flynn was originally from London but moved to Brighton in August 2001 and secured a casual job at the Brighton Centre.