‘Narcissist’ murdered partner after she ended relationship, court told
Stephen Sexton is on trial at Winchester Crown Court charged with the rape, coercive control and murder of Joanna Derkacz
Last updated 20th Oct 2026
A 37-year-old woman was strangled to death by her “narcissistic” partner who had an “anger problem” and killed her after she had ended their relationship, a court has heard.
Stephen Sexton is on trial at Winchester Crown Court charged with the rape, coercive control and murder of Joanna Derkacz at their home in Nevison Way, Waterlooville, Hampshire, on December 28, 2023.
Nicola Shannon KC, prosecuting, told the court the body of Ms Derkacz was discovered on her own bed by her sister Arleta Derkacz, who came out of the house screaming: “He has killed my sister.”
The prosecutor said the 39-year-old defendant had become increasingly controlling towards his partner for more than a year before her death.
She said: “We say he had become increasingly controlling, leading on to the ultimate acts of intimate and physical control – rape and then murder when Stephen Sexton realised that she had determined to get him out of her life.”
Ms Shannon said Sexton had been “violent and threatening” to Ms Derkacz and she had told her sister he had strangled her on one occasion before she had managed to push him away.
The prosecutor said their relationship “took a critical and decisive turn” on December 10 when he broke her laptop “in a fit of anger” when she had come home 20 minutes late from an evening out with friends.
After she then left the house to stay with a friend, Sexton reported her missing to police. Ms Shannon said he was “no doubt hoping that they would find her for him”.
But the prosecutor said that after Ms Derkacz returned, she asked Sexton to move out but agreed for him to stay until the litter of puppies recently born to their dogs had been sold.
Ms Shannon said police visited Ms Derkacz on December 11 for a welfare visit, during which she described Sexton as “very controlling” and “narcissistic” and that “he didn’t like it when I go out”.
The prosecutor said Ms Derkacz had also told officers that Sexton had assaulted his ex-wife, Tara Sexton, and Ms Shannon said he had been convicted of this offence and for damaging her phone.
Ms Shannon added: “Tara Sexton was assaulted when she resisted. Joanna Derkacz was killed when she ignored him and chose to go her own way.”
Ms Derkacz also told the police officers that Sexton had “threatened to take the puppies from me”, but when they replied that this was not a reason to stay, she said: “Well it is for me.”
Ms Shannon said: “It is one of the tragedies of this case, that although Joanna was wary and there were in retrospect so many red flags, neither she nor the officers seem to have realised how far Stephen Sexton might go when he realised she was slipping from his grasp.
“Her optimism and compassion may have cost her her life.”
Ms Shannon told the jury a post-mortem examination showed Ms Derkacz died of compression of the neck.
She added that intimate swabs revealed semen with DNA that matched the defendant.
She said this dated to around the time of Ms Derkacz’s death and the Crown’s claim this would have been as a result of rape as the sex at that point would not have been consensual.
Sexton, of Totton, Southampton, denies the charges and the trial continues.