A marine engineer said 'I'm sorry' after raping and murdering his girlfriend, a court heard.
Stephen Sexton, 39, muttered the apology to Joanna Derkacz's sister after she found her sibling's lifeless body, jurors were told.
Arleta Derkacz said Sexton appeared 'petrified' and had 'dead eyes' when she arrived at the home he shared with her sister.
Arleta told how she pushed past Sexton to discover Ms Derkacz's 'grey' body on her bed, having allegedly been choked by her partner of three years.
She also claimed that Sexton, now holding a knife, told her 'I'm sorry' as she ran out of the house in Waterlooville, Hampshire, shouting 'you killed my sister.'
Sexton, a father-of-one, is on trial accused of strangling Ms Derkacz, 37, after subjecting her to 12 months of 'controlling and coercive' behaviour.
Prosecutors say moments after murdering her, Sexton contacted sex workers as he was 'aroused'.
Ms Derkacz, a recruitment consultant, was found dead at their home in Waterlooville on December 28, 2023.
Sexton denies murder, rape and coercive or controlling behaviour.
Stephen Sexton, 39, is accused of strangling recruitment consultant 37-year-old Joanna Derkacz
Prosecutors said Sexton's 'first thought after the point of death was to try and find prostitutes'
Ms Derkacz was found dead at their home in Waterlooville, Hampshire, in December 2023
On Friday, jurors at Winchester Crown Court, Hampshire, were played a recorded police interview with Arleta, Ms Derkacz's sister.
She told how she went to check on her when she didn't answer her phone as it was unlike her not to pick up.
Arleta said: 'I rang the doorbell once, no answer. Second time, no answer. The third time was really long, no answer.
She told how she then opened the door and Sexton came downstairs looking 'really scared'.
'I haven't seen him for over a year because we didn't speak and I wasn't happy and Joanna knew I didn't want her to be with him,' she said.
'I asked him, 'Where is my sister?' and he said, 'She is not here.' I could see he was lying, and he was shaking.
'He said, 'She is not here,' and I said, 'You're lying. Where is my sister? ' He said, 'She went out to see her friends,' and I said, 'Where is my sister? I know she is here. Where is she?' and again, 'She went to see her friends'.
She told how she pushed Sexton to one side and ran upstairs.
'The first I saw was her black legs, then I saw her face. It was grey and turned to the side, and then her hands,' she said.
'And I didn't even get in there and ran downstairs and said, 'You killed my sister'.
'He was standing in the kitchen with a kitchen knife. He pointed the knife into his hand, and I ran out, and I just started shouting like an animal, 'You killed my sister.''
Arleta said that her partner who was waiting outside then pulled her away to his car because he was worried that Sexton might hurt her if she went back into the house.
When asked what Sexton looked like when she walked into the house, she said: 'He was shaking. He looked petrified, scared. He looked like he was, like he had a rough night last night drinking on drugs or something. He didn't look fresh.
'His eyes were kind of like dead. When I asked him, 'Where is my sister?' He replied, 'She's not here.''
'He was normally, he sounds very loud and confident and this time he had a very fragile voice and very soft. Not very loud. Just like 'she's not here, she's not here'.'
She said: 'I think I asked him three or four times, 'Where is she and who is she with'. He couldn't tell me. He said he didn't know.
'Things like that happened in the past when he was abusive to her, she was finding comfort in her friends. I don't know who it was.
'He was probably trying to use this as an excuse. He knew this happened before so he just said on she went out to see her friends so I said 'Where? What friends?'
'He couldn't tell me because he didn't know. Again, I said, 'Where is my sister?' and he said, 'I don't know.'
'I was still hoping that she was fine, but she wasn't.'
Arleta said that as she was running out of the house, she thought that Sexton said, 'I'm sorry.'
She said: 'I am not sure but I think he said 'I'm sorry'. When I went downstairs and the way he looked at me it was almost like waiting for me to give him a privilege to do it or me to say something so he could do it.
'So I just went downstairs, and he said something when I left, and I remember thinking he said 'I'm sorry.''
Jurors also heard the 999 call made by Lucasz Dylewski, Arleta's partner on December 28, 2023.
In the call Arleta could be heard screaming and crying.
A neighbour was talking on the phone and said: 'He's just killed her sister. I am a neighbour and someone has killed her sister.
'I don't know who she is. She said that she is her sister. She said she is dead and has been murdered.
'Everyone's out here trying to help the girl. No one has seen anything.
'Joanna and Stephen lived there. I was upstairs, and I heard screaming in the middle of the road. I thought someone had been run over.'
The trial continues.