A shocking case in the UK has highlighted serious failings by police and child protection institutions, after a rapist with an unexecuted arrest warrant for 18 months ended up killing his partner’s 2-year-old daughter.
Harrison Simpson, 22, was sentenced last week to life in prison and must serve at least 28 years for the “sadistic” murder of Isabelle Welsh, who died in September 2025. The girl’s mother, Alexandra Walker, 26, was also found guilty of murder and sentenced to life imprisonment with a minimum of 21 years, The Times reports .
The couple had started dating just three months before the murder, after meeting on Facebook.
Cleveland Police have admitted they failed to execute an arrest warrant issued by Teesside Magistrates’ Court in March 2024, allowing Simpson to remain free, form a bond with Walker and live with her and her daughter.
The warrant was issued after Simpson failed to appear in court for violating a protective order against a former partner, who had reported that he had harassed and threatened her.
Police stated that they had made several attempts to find and arrest him, but were unsuccessful.
“We acknowledge that the period during which Simpson had an outstanding arrest warrant falls far short of acceptable standards,” the police response said.
During the trial, it was proven that Simpson had physically and sexually abused the little girl for months before her death.
Isabelle suffered a fatal brain injury after her head hit a hard surface during a violent concussion on September 13, 2025. She died a day later in hospital.
It was not possible to prove which of the two defendants had caused the fatal injury. Walker stated that he had been sleeping that morning after drinking heavily the night before, while Simpson refused to give his version of events.
Just 12 days before her death, Walker had taken her daughter to the hospital for a leg injury. Tests revealed she had a fracture.
A nurse immediately raised concerns about the child’s safety, but doctors accepted the mother’s explanation and took no further action.
The nurse testified that Walker reacted aggressively when the possibility of notifying social services was mentioned and asked to be seen by another doctor.
Just 11 days later, Isabelle returned to the hospital with fatal injuries.
The nurse burst into tears during her testimony, recalling that the little girl was “covered from head to toe in bruises.”
The autopsy revealed:
21 broken bones, including the skull and spine;
97 soft tissue injuries;
hemorrhage in the brain.
The prosecution described the case as one of the most serious cases of violence against a child.
The local child protection center had been in contact with the family twice more during the four weeks before Isabelle’s death, but on both occasions no action was taken.
Four days before the tragedy, a health visitor chose to contact the family only by phone and did not go to see the child at the apartment.
Prosecutor Richard Wright told the court that without even seeing Isabelle, the health worker closed the case by noting that there were no concerns.
However, following the murder, a review by local authorities concluded that decisions not to escalate the case had been “appropriate”, despite the tragic outcome.
The trial found that Isabelle was a happy and healthy child before Simpson entered her life.
Walker had begun to suspect her partner’s behavior, especially since he insisted on washing the girl alone. She even checked the sex offenders’ register, but couldn’t find his name.
Walker’s mother had also warned her daughter that her granddaughter appeared to be being abused.
After discovering the failure to execute the arrest warrant, Cleveland Police announced that they have changed their procedures for managing wanted persons.
According to authorities, a new system for monitoring arrest warrants has already been established, while high-risk cases are reviewed daily by police leaders.
The Hartlepool and Stockton-on-Tees Child Protection Partnership also stated that after Isabelle’s death, a plan of measures was drawn up, which was immediately implemented and continues to be monitored to avoid the recurrence of similar cases.Top Channel