Woman and new partner killed by ex in 'ferocious, merciless and sustained' attack

• WARNING: This article contains distressing details.

A woman told police her ex-partner had threatened to kill her if she ever got another boyfriend days before she and her new love interest were murdered in a "ferocious, merciless and sustained" knife attack, a court heard.

Katie Higton, 27 and her partner Steven Harnett, 25, were found dead at an address on Harpe Inge, Dalton, on the morning of 15 May 2023.

Katie had 99 injuries to her body, including five stab wounds. There were also stab wounds to Ms Higton's face and evidence she had tried to defend herself, Leeds Crown Court heard.

Steven had been stabbed or slashed 24 times.

Marcus Osborne, 34, admitted murdering his former partner and her new boyfriend at a hearing in July at Leeds Crown Court. He also admitted the false imprisonment and rape of another woman.

On Thursday (29 February), Osborne stood in the dock wearing a long grey sweat-shirt for the first day of sentencing. The families of both Katie and Steven were in court.

Prosecuting, Jonathan Sandiford KC said Osborne committed a "pre-meditated and brutal double murder", brought about by sexual jealously.

He asked the court to consider a whole life sentence, which means he would never be released from prison.

He said Katie and Steven had begun a relationship shortly before 15 May 2023 and Katie had previously been in a relationship with Osborne for five years.

Ms Higton left Osborne four days before her death and made a statement to police about his behaviour, which included how she was not allowed her own social media accounts.

She described to police how the relationship had become coercive, controlling and physically abusive.

She told the police the first physical violence happened two years prior when Osborne threw a pet cat at her and grabbed her by the throat. After that there were occasions he would be physically and verbally abusive to her.

A work colleague said he would have been 'battered' by Osborne if he gave Ms Highton a lift home from work.

The man said after they stopped working together, Katie deleted him on social media, before adding him back shortly after, and explaining the defendant didn’t want her speaking to him now they no longer worked together.

Katie decided to leave Osborne following an assault on 28 April 2023 - the "final straw", the prosecution said.

Osborne pushed her, causing her to strike her face on the kitchen worktop, before grabbing her by the hair and punching her in the face. As she got up to leave, he pushed her in the back.

The assault continued with him kicking her in the ribs and shouting at her to get out.

As a result, Ms Higton suffered bleeding to her ears and "significant bruising to legs arms back and ribs." She filmed some of the injuries on a mobile phone.

Katie Higton said it was a struggle to leave, but she was "proud of herself", the prosecution said.

The court has heard how Osborne messaged Katie to say he would change, but she "remained resolute" not to go back.

On 10 May 2023, Katie Higton made a report to police.

Mr Sandiford KC, for the prosecution, told Leeds Crown Court: "Snapchat messages were exchanged between the defendant and Katie Higton, saying she did not want to see him following threats."

Ms Higton went to Huddersfield police station that same day, but no officers were available to see her, Mr Sandiford KC said.

In a Snapchat conversation at 1:51 BST that day, Osborne was threatening, saying: "If I find out you're seeing someone, I'll end you fully."

An appointment was made for police officers to see her at 8am the following morning.

The court were told that Osborne said if Ms Higton did not return to him, he would kill himself.

On 12 May 2023, Marcus Osborne was arrested and interviewed for domestic violence offences.

He was released on bail with conditions not to go back to Ms Higton's home, which she previously shared with Osborne, to allow her to move back in.

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

The following day, Osborne asked a neighbour to tell them when Ms Higton was at home.

On 14 May, the defendant was seen in the area.

Prosecuting, Mr Sandiford said he was "keeping watch" on the house and who Katie was with.

A neighbour said "He appeared to be agitated and looking towards [the house]", according to the prosecution.

On the day of the murder Katie and Steven had been to Vue cinema. That night, Osborne was then seen on CCTV walking back from a pub to Harpe Inge.

Sometime after midnight, he went to the house but was reminded by a woman there about his bail conditions.

Armed with a knife, he punched the woman inside the house, and demanded to know where Ms Higton was. She described seeing "rage in his eyes and thought he was going to kill her there and then".

The court heard how Katie was 'lured to her death' by Osborne.

He told the woman in the house to contact Ms Higton and tell her to come home, which she did.

In a police interview, the woman said she feels guilty for contacting Ms Higton before her murder.

A neighbour said they heard muffled raised voices at about 1am on the morning of 15 May, including 'male voices which sounded very angry', before a door was slammed.

Mr Sandiford said Katie was heard screaming by the other woman at the property "stop Marcus what are you doing”, while he said: "I warned you, this is your fault this is happening."

Mr Sandiford said: "The last time she saw Katie alive, she was on the floor in the hallway and the last words she said was 'Marcus, I can’t breathe'."

Both her lungs had been punctured in the attack.

It was "like a horror story, with blood pouring out of Katie", the court was told.

The woman wanted to go to Katie, but Osborne told her: "She’s going to die on her own and you’re going to sit up here while she dies on her own."

He then went upstairs to wash his hands and change his clothes because he was covered in blood, the court heard. This was the first of three changes of clothing that evening.

The defendant said he wanted to kill Steve Harnett, who Katie Higton had been to the cinema with, Mr Sandiford KC said.

Using Katie's phone, Osborne sent a message to Mr Harnett on Snapchat, to lure him to the house. Harnett believed he was messaging Katie, and was told to use a side door so he wouldn't see Katie's body.

Mr Sandiford said: "It would appear in the taxi he had second thoughts and tried to call her on route. Unsurprisingly, the defendant did not answer… Steve Harnett asked if she was sure no one would see him and he replied 'no course not. Scared?'

"It appears he was concerned about what the defendant would do and said 'no, just asking, don’t want man coming and kicking door'.

"His concern, it seems, was the very thing that was happening."

Harnett was immediately stabbed by Osborne and died quickly.

One of the stab wounds went through Mr Harnett's lungs and heart, prosecution barrister Jonathan Sandiford KC said.

The court heard how Osborne remained 'calm' during the double murder. The woman in the house during the attacks said he "laughed" with a "chilling" demeanour.

Osborne raped a woman in the house following the attacks, whom he had held captive in the house overnight, at knifepoint, before running himself a bath, the court was told.

The court heard there were four children in the house at the time of the murders.

Marcus Osborne showed off the victims' bodies "like he was proud of what he'd done", the court heard.

"I know I'm going down for murder, I just need to sort some stuff out," Osborne told someone in the house, according to the prosecution.

A number of knife-tip injuries sustained by Mr Harnett were intended to "torment, not to kill", Leeds Crown Court heard.

Mr Sandiford said an injury sustained by Mr Harnett, which happened while he was thought to have still been alive, showed "sadistic conduct" by Osborne.

Defence, John Elvidge KC, said Osborne 'felt unwanted' and that his father wasn't in the picture. The court heard that Osborne was placed in a school for children with special educational needs and he was able to achieve some qualifications.

Mitigating, Mr Elvidge KC said Osborne "pleaded guilty at the earliest opportunity available to him in these proceedings" and credit should be given for the early plea and it saved witnesses "having to worry about giving evidence and reliving events and their recollection".

Katie Higton's mother spoke in court saying Osborne is "a monster of the worst kind".

She added: "I no longer live, I exist in a torturous world without my baby. I've never known anything so vile."

A written statement from her father, Robert Higton, said: "I couldn't have asked for more when she was born.

"She has been so cruelly ripped away from me. I'll forever be expecting a call or text message from Katie, but I know it'll never come.

"The way Katie was taken from me gives me nightmares.

"To hear the details of what she endured, not only during the course of her death, but the weeks before, shook me to my core," he wrote.

"Her death has turned my world into a horror story."

Janine Parkin, Steven Harnett's mother said her world came "crashing down" when she heard rumours something had happened to her son.

"I was in a state of panic. My heart sank and I began fearing the worse.

"Imagine the horror when I arrived home when everyone was staring at you, telling you to sit down.

"My son had been brutally murdered. I felt my heart shatter into 1,000 pieces."

Osborne was earlier sentenced to seven years in a Young Offenders' and was also previously jailed for 16 weeks for common assault, as well as serving 51 months in prison for GBH with intent - against a former partner towards whom he was violent.

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