A MONSTER who murdered his ex and mutilated her new boyfriend’s body has been jailed for life.

Katie Higton, 27, was “ferociously and mercilessly” murdered alongside Steven Harnett, 25, inside her home in Huddersfield in May last year.

Her ex Marcus Osbourne, 35, brutally attacked the pair – leaving Katie with 99 injuries.

He then attacked her new lover, leaving his body mutilated and covered in 24 wounds.

The killer has today been thrown behind bars for life, after last year admitting to two counts of murder.

He also pleaded guilty to the false imprisonment and rape of another woman on the same evening.

At the time of the killing, Osbourne said: “Romeo and Juliet can die together.”

It was heard that he had been released from prison just days before committing the violent crimes.

Osbourne was jailed in 2013 for four years and ten months after he broke a previous girlfriend’s jaw in three places when she ended their relationship.

He was caged again for 16 weeks in 2015 after attacking another girlfriend, again when she split-up with him.

Osbourne told that woman she would “end up in a box” if she finished with him.

Both Katie and partner Steven were knifed to death during the horror attack, which came just hours after a cinema date.

She had shared a smiling selfie on her Snapchat just 12 hours before police found her dead in her own home.

Katie’s former brother-in-law told how his sibling dated the mum for seven years and was the dad of her oldest two children.

He said the children were “in the property when the incident took place”.

Katie was previously in a relationship with Osbourne after they met at the gym where he worked in 2018.

One pal claimed the controlling personal trainer cut her off from her male friends and rifled through her social media.

A week before the murders, he sent a chilling message to the friend warning him not to speak to Katie anymore.

Speaking today, 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.”

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