A man has been found guilty of murdering his partner’s teenage daughter just hours after she confided in her mother that he had sexually abused her for seven years.

Bernadette Walker wrote in her diary that after revealing her ordeal her mother, Sarah, branded her a liar and threatened to kill her. In a heartbreaking entry, which can now be revealed she wrote: “What kind of parent wouldn’t believe their daughter?”

The 17-year-old fled to her grandparents’ home but the following day was collected by stepfather, Scott Walker, 51, who killed her during the journey home and then dumped her body, which has never been found.

The couple then attempted to cover up the murder by concocting a story that Bernadette (known as Bea) had run away.

They did not initially report her missing for three days and then even sent messages from her mobile phone to suggest she was still alive. In one phone call to police, Sarah lied and told detectives it was not the first time she had run away from home.

They successfully misled the police for seven weeks before they were eventually arrested in connection with the teenager’s disappearance.

On Monday, Scott Walker was convicted of murder while Sarah was found guilty of two counts of perverting the course of justice with the knowledge that her daughter was dead.

Cambridge Crown Court heard how on July 16 last year Bernadette had told her mother that Scott, who was not her biological father, had sexually abused her for a number of years.

However, after revealing her ordeal, she wrote in her diary: “Told my mum about my dad and the abuse. She called me a liar and threatened to kill me if I told the police.

She went on: “I feel nothing right now ‘cause I always thought mum would deal with it and it would all go away. But no, he’s still here telling me I made it up. What kind of parent wouldn’t believe their daughter?”

Bernadette Walker was last seen alive on July 18 last year, and her body has never been found

Credit: News Scans

The diary was discovered by police in her backpack which was stashed in a lockup garage regularly visited by Walker.

During the trial, the jury heard that Walker’s phone was off between 11.23am and 12.54pm on July 18, and police believe it was during this 90 minute window that Bernadette was murdered.

When Walker’s phone reconnected to the network at 12.54pm the first call he made was to Sarah, which lasted for more than nine minutes.

During that call it is thought Walker confessed to his partner he had killed her daughter and secured her agreement to help him cover up the crime.

Sarah Walker was not married to Scott Walker but had changed her surname to Walker by deed poll.

At the time of Bernadette’s disappearance, Scott and Sarah Walker were living at the same address but Sarah Walker was in a relationship with another man.

Scott Walker and Sarah Walker, the parents of Bernadette Walker. At the start of the trial, Walker was accused of killing his step-daughter, Bernadette, 17, and then forming an 'unholy alliance' with wife Sarah to hide crime

Credit: East Anglia News Service

Detective Inspector Justine Jenkins, from the Beds, Cambs and Herts Major Crime Unit, said: “I am pleased we have been able to get justice for Bea after what has been such tragic circumstances.

“I just hope now we may get the answers we need to be able to find her and lay her to rest. If anyone has any information about this investigation which may help us find Bea, please get in touch.

“We may never know the truth about what Scott did and why, but we do know Bea had made allegations of abuse against him.

“My plea to anyone who may have been subjected to abuse is to speak to us. Bea thought she could confide in her own mother, who should have been able to protect her, but instead she met a tragic end.”

The couple will be sentenced on Sep 10.