A marine engineer who raped and murdered his girlfriend had previously strangled her, the victim's sister told police. 

Stephen Sexton, 38, strangled Joanna Derkacz, 37, a recruitment consultant, after their relationship broke down following 12 months of 'controlling and coercive' behaviour, a court heard. 

Sexton, a father-of-one, is accused of raping Miss Derkacz, strangling her to death - and then making two separate visits to prostitutes while her body lay undiscovered at his flat in Waterlooville, Hampshire. 

The jury at Portsmouth Crown Court heard how Arleta Derkacz, Miss Derkacz's sister, told police she became worried about her sister's welfare as the relationship deteriorated because he had strangled her in the past. 

The court was shown a police video interview which showed Arleta saying how her sister was 'happy and excited' when she first began her relationship with Sexton, having not been 'very lucky' with former partners.

She said: 'He seemed to be quite confident and a good bloke and had his own business and seemed to be quite decent.'

But as time went on, Miss Derkacz complained of Sexton smoking 'too much' cannabis and drinking excessive amounts of alcohol after the couple had moved in together to rent a property.

The court heard Arleta suspected further issues were unfolding in the relationship when Miss Derkacz revealed she wanted to buy a property by herself.

Arleta Derkacz said that when Miss Derkacz went out with friends without Sexton she would return home to find Sexton 'very jealous'. 

'I know he didn't go out with her too much so whenever she did (go out) he was not happy,' Arleta said, recounting a time when Sexton grabbed her laptop off her and smashed it. 

'The next day she rang and was crying and he was kicking off.'

Arleta said her sister needed someone to 'take care of her' but found herself trying to look after Sexton, who lost his job.

Arleta said: 'Jo was stronger than him and would comfort him. She was giving her all, she was providing.'

Arleta said she was told about an incident where Sexton put his hands around Joanna's neck before she 'pushed him away'.

She added: 'It was surprising when she told me he had strangled her.'

Miss Derkacz kept on trying to make things work with Sexton, the sister said, before adding: 'She was giving him chances over and over again. [Joanna said] she would need to end her own life to end (the relationship).'

Despite being a 'confident' person, Miss Derkacz withdrew and took up therapy to find out 'why she makes the wrong decisions' according to her sister.

The couple's relationship broke down and the court was previously told how Miss Derkacz had wanted the relationship to end.

However she allowed Sexton to stay in their house as they were selling a litter of puppies - on the condition that he left once this was done.

But on December 27, Miss Derkacz accused Sexton of going through her things and taking a book a male friend had given her which had an inscription written inside the cover.

Though he denied it, the book was eventually found by police in the wardrobe used by Sexton.

Miss Derkacz told Sexton that she wanted him gone by midday the following day.

Prosecutor Nicola Shannon KC told the jury that Sexton returned home that night and strangled his partner to death, fracturing her neck in three places with his forearm or the crook of his elbow. 

He is then alleged to have left the house to meet two prostitutes.

Arleta Derkacz discovered her sister's body when she came over the next morning at around 11.30am after becoming concerned when her sister did not answer her phone.

Opening the case, Miss Shannon KC said: 'Joanna and Stephen had been in a relationship for the last three years - one which the prosecution say had become controlling and coercive over the year before.

'On occasion it had been violent and threatening. By December 2023, Stephen Sexton's behaviour had frightened Joanna.

'She told her sister that on one occasion he had tried to strangle her but that she had managed to push him away.

'He also took her phone more than once and broke a phone and her laptop in fits of anger.

'Over the months it had involved jealousy, paranoia and attempts to control and isolate her.

'They had already had one break up at the beginning of the year and again in the summer, then in December things took a critical and decisive turn.'

The court previously heard from prosecutors how Sexton's motive for killing Miss Derkacz was 'simple' because 'when it became clear that she had finally decided to exclude him from her life, he decided that she could not be allowed to go on without him'. 

Sexton denies murder, rape and controlling or coercive behaviour following the incident.  

The trial continues.