The 21-year-old was killed in August 2020 by Jonathan Creswell, a horse trainer and showjumper who was in a relationship with Simpson’s sister.
Creswell had called the emergency services after assaulting Ms Simpson, claiming to have found her hanging from a stairwell. Simpson died six days later.
Police initially treated her death as suicide, only upgrading the incident to a murder investigation following the intervention of detective James Brannigan.
Creswell was charged with her murder but died at his home a day after his trial commenced in April last year.
Mr Brannigan, who led the investigation into Ms Simpson’s killing, said the sector needs to take a look at how it safeguards young people.
“If you take your child to soccer, rugby, Gaelic, swimming, there are safeguarding measures,” he told the Sunday Times this weekend.
“In the equestrian sector, there are none. Predators know that these kids, especially girls, will do anything to stay with horses.
Creswell (36) died at his home in April 2024, before his trial began
“Creswell was a paedophile. He started relationships with schoolgirls. When he came out of prison after the assault on Abigail Lyle, and it was a brutal assault, the local hunt had a ‘welcome home’ party for him in Armagh.
“The cases going through the public prosecution service here of incidences taking place in the equine industry is shocking. The equine industry is riddled with this.”
Ms Simpson’s story is the subject of a three-part series, Death of a Showjumper, coming soon to Sky and Now TV.
It features Mr Brannigan and Co Armagh journalist Tanya Fowles who, after Simpson’s hospitalisation, alerted police that Creswell had been sentenced to six months in prison in 2010 for violently assaulting his former partner.
When the journalist’s calls to PSNI in Derry were ignored, she informed Mr Brannigan, who had previously led an investigation into Charlotte Murray (34), who disappeared in 2012 and whose remains have never been found.
Ms Murray’s former fiancé, Johnny Miller, was later found guilty of her murder.
Mr Brannigan’s team only became the lead investigators on the case five months after Ms Simpson’s killing.
“I had to do it myself behind the scenes because I knew there was animosity towards me doing it,” he said.
“Simpson was dead in a car, covered in bruises, and the guy [Creswell] driving the car said, ‘She’s hung herself.’ This guy had a brutal history of domestic violence.
“What stood out to me was the fact that people were going to the police with information. Intelligence was coming in that should have made any police officer sit up.”
The PSNI’s initial alleged missteps when investigating Simpson’s death included a failure to factor in an incident in which Creswell exposed himself to a female in a stable yard in 2016 and then fled across the border.
Katie Simpson (21) was murdered by Jonathan Creswell in August 2020
Police apologise as watchdog finds Katie Simpson’s family ‘failed’ by probe
An independent review into Creswell’s case is under way and is being conducted by Jan Melia, a former Chief Executive of Women’s Aid Federation.
“The equine industry is an area of concern and has been included in the review,” she said.
The Police Ombudsman is dealing with a number of complaints over the case, including one from Ms Fowles over the PSNI’s failure to respond to her concerns over Creswell.
The PSNI has said the Ombudsman had notified seven officers that they were under investigation following complaints about the handling of the case.
Four of those officers have since retired.