A woman who was allegedly raped and murdered by her 'narcissistic' boyfriend dreamed of 'achieving something in her life' and building a family, her grieving sister told a court.
Stephen Sexton, 39, and Joanna Derkacz, 37, had been together for three years and the relationship was initially welcomed by her sister who had 'treated him as family'.
Ms Derkacz, 37, a recruitment consultant, was found dead at their home in Waterlooville, Hampshire, on December 28, 2023.
Moments after murdering her, Sexton contacted sex workers as he became 'aroused', prosecutors said.
Sexton denies murder, rape and coercive or controlling behaviour.
Giving evidence at the trial, at Winchester Crown Court in Hampshire, on Monday, Ms Derkacz's sister, Arleta, wiped away tears as she said her sister 'wanted to achieve something in her life, to buy a house, and have a family'.
Arleta went on to tell jurors that she had a good relationship with Sexton and believed him to be a good man, but now regrets ever having thought so highly of him.
Stephen Sexton, 39, is accused of killing his girlfriend, 37-year-old Joanna Derkacz
Ms Derkacz's sister, Arleta, wiped away tears as she said her sister 'wanted to achieve something in her life, to buy a house, and have a family'
Moments after murdering Ms Derkacz, Sexton contacted sex workers as he became 'aroused', prosecutors said
Ms Derkacz was found dead at their home in Waterlooville, Hampshire, in December 2023
She said: 'He was very confident. He was a good bloke, that's what I thought. I had a good relationship with Stephen, that's what I thought.'
She added her sister was 'very excited' after having met Sexton on the dating app Tinder.
Arleta, from Chichester, West Sussex, said Sexton would regularly help her own partner on renovation work at their house.
'He built a table in my beauty room. We treated him as family.'
She said she previously thought he was 'the best brother-in-law I ever had. I will regret saying that for the rest of my life,' she told jurors.
Arleta said there was an incident around a year before her sister's death which led to her falling out with Sexton.
Speaking from the witness box, Arleta said: 'I hate him. I treated him as family, but I started having these feelings on him. I hate him.
'So many of my friends wish him dead, I don't.
'He disappointed me because I trusted this person and in that moment I saw him show his true colours.'
Arleta said Sexton had made up 'lies' by claiming she had cheated on her long-term partner, Lucasz Dylewski.
She said Sexton is 'sick to his head' for coming up with the lies and that he called her a 'f****** b****'.
On December 28, 2023, Arleta went with her partner to Ms Derkacz's home in Waterlooville, because she wasn't returning her calls.
Arleta said Sexton appeared 'petrified' and had 'dead eyes' when she arrived at the home he shared with her sister.
She told the court how she pushed past Sexton to discover Ms Derkacz's 'grey', lifeless body on her bed, having allegedly been choked to death by her partner of three years.
Arleta told jurors that when she came downstairs, she saw Sexton holding a 'big kitchen knife', and that she thought he said 'I'm sorry' as she ran out of the house, shouting 'you killed my sister'.
The jury heard her tell detectives: 'I just saw my sister being dead. He had nothing to lose; he'd just killed my sister. He could have followed me upstairs and stabbed me.'
The court heard she was pulled out of the house by her partner. She said she was 'petrified' and 'didn't look back'.
Arleta said: '[Miss Derkacz] did say that he was trying to choke her, but she managed to get away and she managed to push him off.
'I know he was aggressive, especially in the last year, and sometimes things he was saying on drugs.'
The trial continues.