A father accused of murdering his teenage stepdaughter 'showed no emotion' when police asked him about her disappearance, a court heard.
Bernadette Walker, 17, was last seen alive on July 18 last year when Scott Walker, who is not her biological father, collected her from an overnight stay at her grandparents' house in Peterborough, Cambridge Crown Court heard.
Prosecutors allege that 51-year-old Scott Walker killed Bernadette to 'prevent her pursuing her allegations of sexual abuse any further'.
Her body has not been found despite police searches.
Scott Walker is then accused of forming an 'unholy alliance' with Bernadette's 38-year-old mother Sarah Walker to mislead investigators, sending messages from Bernadette's phone and social media accounts to claim that she ran away, said Lisa Wilding QC, opening the prosecution case.
Scott Walker is accused of murdering his stepdaughter Bernadette in July last year. She was last seen being collected from an overnight stay at her grandparents' house in Peterborough
She said Sarah Walker, who is not married to Scott Walker but changed her surname by deed poll, reported photography student Bernadette missing on July 21.
Sarah Walker lived with Scott Walker but their relationship had broken down and she had a new boyfriend, Christopher O'Connell, Ms Wilding said.
She said that police officer Elizabeth Aspland went to search Bernadette's bedroom on July 23 as part of the missing person's investigation.
Ms Wilding said Scott Walker was in the house when PC Aspland arrived and he 'became tearful'.
'He told her that Sarah was in a relationship with another man, Chris,' said Ms Wilding.
Scott Walker is accused of forming an 'unholy alliance' with Bernadette's 38-year-old mother Sarah Walker, pictured together, to mislead investigators, sending messages from Bernadette's phone and social media accounts to claim that she ran away
'Bernadette had made some false allegations against him, Scott, and he thought that was done probably to get him, Scott, out of the house so Chris could move in.'
Scott Walker 'showed no emotion about Bernadette but was emotional about losing Sarah to her new boyfriend' when police spoke to him on a separate occasion on September 9, Ms Wilding said.
She said Scott Walker told police he 'couldn't remember the exact location (Bernadette) disappeared from as he had a lot on his mind at the time'.
'He drew a map of the area but told police he wouldn't be able to locate the spot,' she said.
'He showed no emotion about Bernadette, but was emotional about losing Sarah to her new boyfriend.
'He was specifically asked if (Bernadette) had her phone with her when he picked her up that morning.
'He said he didn't know but he didn't see or hear one.'
Prosecutors said Scott Walker told police he 'couldn't remember the exact location (Bernadette) disappeared from as he had a lot on his mind at the time', and that he 'showed no emotion' towards her
He said she ran away when he stopped the car.
Ms Wilding said police found Bernadette's rucksack in a lock-up used by Scott Walker.
'There's evidence Bernadette had her period at the time she disappeared,' said Ms Wilding.
'You can see she had sanitary protection in her bag along with basic toiletries and clothing.'
She said that the bag being inside the lock-up and not taken with Bernadette 'speaks volumes about what really happened'.
Ms Wilding said police spoke to Sarah Walker on September 9 at her new boyfriend's address.
Sarah Walker said she 'didn't believe the sexual allegations Bernadette made against Scott, but blamed Scott for arguing with her on the way home causing Bernadette to disappear', Ms Wilding said.
Bernadette's mother also made allegations against Scott Walker, saying that she thought he 'used her thumb while she was asleep to access her phone so he could track her', Ms Wilding said.
'She said he spied on her at (her new boyfriend) Chris's house and sent her pictures, so she knew he was there, and he messaged her repeatedly when she was at Chris's house until he got a reply.'
Sarah Walker also told police Scott Walker should have moved out after they split up but had not, Ms Wilding said.
Scott Walker denies Bernadette's murder on or after July 18 last year and four counts of perverting the course of justice.
Sarah Walker denies two counts of perverting the course of justice.
The trial continues.