Police issued warrant for paedophile Harrison Simpson's arrest 18 months before he killed partner's toddler

Police failed to execute an arrest warrant against a paedophile in the 18 months before he killed his partner's two-year-old daughter.

This story contains details some readers may find distressing.

Harrison Simpson, 22, and the toddler's mother, 26-year-old Alexandra Walker, were jailed last week for murdering Isabelle Welsh after weeks of abuse.

Isabelle collapsed at her home in September last year following a "massive head injury". A post-mortem found she suffered 21 broken bones in the weeks leading up to her "sadistic" death.

Cleveland Police has told Sky News that Simpson was charged with breaching a non-molestation order in March 2024.

"A warrant for his arrest was issued that same month after he failed to appear at court," a statement said. "Multiple enquiries and arrest attempts were carried out to try to locate and arrest him but these proved unsuccessful."

Isabelle's family was told about "the circumstances surrounding the outstanding warrant early on in the investigation", the force added.

"We recognise the time Simpson had an outstanding arrest warrant is far from adequate. A review of this was immediately conducted upon his arrest for murder," the statement added, after first being reported by The Sunday Times.

Cleveland Police said several changes were made after the review, including increased visibility of outstanding warrants, a comprehensive data system to track them, and daily reviews of the highest-risk cases.

A 'sadistic' death and 21 broken bones

Simpson and Walker were convicted of murder and child cruelty, while Simpson was also found guilty of sexually assaulting the toddler.

When paramedics arrived at Walker's house in Thornaby on 13 September 2025, they found the two-year-old at the foot of the stairs without a pulse.

The trial was told that as Isabelle was dying, Walker smoked a cigarette in her kitchen and delayed ringing 999 despite Googling "why would my toddler be bleeding".

She called her stepfather to come round, and it was only on his instruction that she finally rang emergency services.

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There were bruises all over Isabelle's body, including to her head, neck, abdomen, back and private parts. There was blood in her nappy and sick on her face, jurors were told during the trial.

Isabelle was taken to hospital but died the next day.

Prosecutor Richard Wright KC said the toddler suffered weeks of assaults and the head injury "was simply the end point in that campaign of violence".

Eleven days before her fatal collapse, Isabelle was taken to her GP and then to hospital with a broken leg.

Despite the misgivings of some staff, she was discharged after Walker claimed she must have suffered the injury after getting caught in her cot.

Walker began dating Simpson after they met on Facebook just months before - and she suspected he might be a paedophile, saying he preferred to see her with Isabelle and would bathe the toddler without her permission.

Despite being suspicious enough to check the Sex Offenders' Register, Walker did not break up with him.

Simpson refused to answer police questions or testify at trial.

The judge considered a whole life tariff for Simpson but could not be sure if the murder was sexually motivated.

Simpson and Walker were given minimum terms of 28 years and 22 years, respectively.

(c) Sky News 2026: Police issued warrant for paedophile Harrison Simpson's arrest 18 months before he k