Bernadette Walker was last seen alive on July 18 last year when Scott Walker picked her up from her grandparents’ home.
Tragically the teenager’s body has never been found after Walker spun a web of lies to dupe police.
The 51-year-old formed an “unholy alliance” with Bernadette’s mum Sarah Walker to make it look like she was still alive and had run away.
The couple sent messages from her phone and social media accounts after reporting her missing to “lay a false trail”.
Walker, who was not Bernadette’s biological dad, cooked up the “devious, wicked” plot after Bernadette told her mum he had been sexually abusing her in a murderous bid to silencer her.
A harrowing diary entry has now been released by police after he was found guilty of murder and two counts of perverting the course of justice.
Bernadette’s mum Sarah Walker was convicted of two counts of perverting the course of justice.
The undated entry seen by jurors reads: “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 said that the other kids matter more. I love feeling unwanted. I feel nothing right now cause I always thought mum would deal with [sic] 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?
“But it’s fine, I’m going to pretend it’s okay till I leave home then I will block them out of my life.
“I’d rather say I’m an orphan than say I have abusive parents who couldn’t give a sh*t about me or what happens to me.
“If I was brave enough I probably would have already left, or just killed myself.”
The court was told heard how Bernadette, who called Walker ‘Dad’, told her mum he had been “sexually abusing her over a number of years”.
She also said he spied on her undressing using cameras hidden in the bathroom and touched her inappropriately in a games room.
The teen was sent to her grandparents’ home in Peterborough after the sickening allegations were made and was said to be “very upset”.
Bernadette kept sobbing and saying she wanted her mum to believe her as she kept repeating: “I’m not lying”.
But she soon turned “quiet” when Walker arrived the next morning to pick her up.
The depraved dad told the court how he was driving Bernadette home that day when she ran off while he rolled a cigarette.
The fiend’s phone was switched off on the day she vanished between 11.23am until 12.54pm – with prosecutors saying he killed her in that period.
His first call after switching his phone back on was a nine minute call to Sarah Walker.
It is then they concocted a grim plan to throw investigators off the scent and make them believe Bernadette was still alive.
The pair kept hold of Bernadette’s phone and continued to send messages to her friends so it looked like she was still alive.
They then lied to police to give them “no hope of finding” Bernadette.
The teen was finally reported missing after three days and a huge search was mounted.
When asked why they waited so long to report her missing, Walker gave a string of excuses – including him never believing she wasn’t safe.
He even posted desperate appeals for information on social media and begged Bernadette to let him know she was OK.
The parents were eventually arrested about a month and a half later when police launched a “no body” murder probe.
Lisa Wilding QC said: “Since the day she disappeared… no-one who knew her or loved her has heard from her.
“She is presumed dead and, as you will come to hear, it’s likely that her body was disposed of, probably in the countryside in the hours that followed her killing.
“The prosecution allege that Scott Walker killed Bea to prevent her pursuing her allegations of sexual abuse any further.
“He then enlisted the help of her mother, his wife, to cover his tracks and to provide them both with some time to formulate the next part of their plan.
“They lied to everyone around them… All parental love and responsibility was gone, if ever it actually existed.”
Walker will be sentenced on September 10.