Killer ‘motivated by sex’ murdered ex and her new partner days after she reported him to police

Marcus Osborne has been sentenced to a whole life order by Leeds Crown Court for the murder of Katie Higton and Steven Harnett

An obsessive ex-boyfriend “executed” a mother of four and her new partner just four days after she reported him to the police.

Marcus Osborne, 35, of Harpe Inge, Dalton in West Yorkshire, has been sentenced to a whole life order at Leeds Crown Court for the murder of his ex-partner Katie Higton and her new boyfriend Steven Harnett, 25.

Ms Higton, 27, had told West Yorkshire Police that she feared Osborne would seriously harm or kill her, after he made repeated threats that he would murder her if she got another boyfriend.

Days later, he brutally stabbed her and Mr Harnett at her home in Huddersfield on 15 May 2023, with both pronounced dead at the scene.

Osborne said: “Romeo and Juliet can f***ing die together now” after the brutal double killing which left Ms Higton with 99 injuries and Mr Harnett with 24 wounds including mutilated genitals.

A family member shouted “I hope you rot in hell” from the public gallery as Osborne was taken away.

Katie Higton, 27, and her new boyfriend Steven Harnett, 25 were brutally murdered by Marcus Osborne on 15 May 2023 (West Yorkshire Police/PA Wire)

Katie Higton, 27, told West Yorkshire Police that she feared Osborne would seriously harm or kill her (PA)

The judge, Mrs Justice Lambert, said the killings were “sexual in nature” and driven by Osborne’s “pathological jealousy”.

She told Osborne: “They were driven by your sexual jealousy arising from Katie’s decision to start a new relationship with Steven.”

“I do not accept (the murders) are explained by your entrenched insecurity about being abandoned as a result of a neglected childhood,” she added.

“Everything you did was motivated by sex and your need to sexually humiliate and degrade.”

The judge also said Ms Higton’s murder was a “merciless and sustained attack on a woman who was completely defenceless”.

Marcus Osborne, 35, of Harpe Inge, Dalton in West Yorkshire, was sentenced to a whole life order at Leeds Crown Court for the murder of his ex-partner Katie Higton and her new boyfriend Steven Harnett, 25 (West Yorkshire Police )

She said that during the attack, which started “before (Ms Higton) even got through the front door”, Osborne was heard saying: “I warned you I was going to kill you… this is your fault this is happening.”

He then raped another woman, who he had held captive in the house overnight, at knifepoint. The court heard four children were in the house during the murders.

The judge said the woman who was held captive in the house described Osborne washing himself between killings, laughing and jeering, later even inviting a neighbour into the living room to see the bodies “as if you were proud of what you had done”.

Steven Harnett died after receiving 24 wounds in the brutal attack (PA)

The court heard that Osborne lay in wait for Ms Higton and launched a brutal attack on her as soon as she came through the door of the house they once shared in Huddersfield, West Yorkshire.

Osborne then used Ms Higton’s phone to pretend to be her and lure Mr Harnett to the house.

Prosecutor Jonathan Sandiford KC said: “The defendant committed a premeditated and brutal double murder motivated by sexual jealousy, a desire to exercise control over Katie Higton, an unwillingness to accept her decision to leave him and her freedom to form a relationship with another man.”

Ms Higton had been in a relationship with Osborne for five years, but left him in early May last year after an assault on April 28 which was “the last straw”.

She later told police the relationship had become “coercive, controlling and physically abusive” in the last two years and that she had been regularly assaulted, including one incident when he threw a cat at her, the court heard.

Osborne used Ms Higton’s phone to pretend to be her and lure Mr Harnett to the house (West Yorkshire Police )

Osborne also has convictions for violent offences against two previous partners in 2011 and 2012, Mr Sandiford said.

In the days before the murders, Ms Higton told West Yorkshire Police Osborne had told her “he would slit her throat if she said what he had done”, and that “if she ever got a boyfriend he would kill them both”.

Osborne was arrested on suspicion of domestic violence offences on May 12 and bailed with conditions not to go back to their home, but spied on her over the following days before taking a taxi to the house on the night of the murders.

At the time the murder was reported, professionals were holding an urgent meeting to discuss ways to protect Ms Higton and her four children.

The court heard he found out about the developing relationship between Ms Higton and Mr Harnett by hacking into her Snapchat account.

A victim personal statement by Ms Higton’s mother Nicola McAlister, read in court, said Osborne was “a monster of the worst kind”.

Osborne had pleaded guilty to two counts of murder and other offences. The judge also imposed 10-year concurrent sentences for the rape and false imprisonment of the other woman in the house.

She told Osborne: “There are no mitigating factors in your case other than your guilty plea. There is no psychiatric or other evidence placed before me to explain or help me understand your actions.

“This is a case of such exceptional seriousness that even a very long minimum term would not be a just punishment. What you did that night was horrific.”

Following her death, Ms Higton’s family and friends paid tribute to her as “the best mum” and said the family was “absolutely devastated” as they placed flowers on behalf of her two eldest children at the scene.

Ms Higton’s former brother-in-law, who asked not to be named, said his brother had been in a relationship with the mother-of-four for seven years and was the father of her two eldest children, daughters aged nine and 10.

He described Ms Higton as “bubbly, outgoing, fun” and “a great mum”.