The trial of Jonathan Creswell, 36, for the murder of Ms Simpson, ended in April last year after his sudden death.
The showjumper, 21, from Tynan, Co Armagh, died in Altnagelvin hospital almost a week after an incident in Gortnessy Meadows, Lettershandoney, in Co Londonderry, on August 3 2020.
Police originally thought she had taken her own life.
It was not until the following year that Creswell, the partner of Ms Simpson’s sister, was arrested on suspicion of murder.
Creswell had previously been jailed after being convicted of assaulting a former partner in 2009.
It has emerged that Creswell was not subject to a risk management plan at the time of Ms Simpson’s death.
Justice minister Naomi Long has now commissioned a review to establish whether opportunities were missed to refer Creswell into the Public Protection Arrangements Northern Ireland (PPANI).
Ms Long’s Alliance Party colleague and Policing Board member Nuala McAllister, had asked the minister if she would commission a Serious Case Review (SCR) under the terms of the PPANI to consider whether there had been potential referral failures in the case of Creswell.
In a written answer, the minister said a SCR was only applicable for cases already managed through PPANI.
As Creswell was not being managed under the arrangements, Ms Long said a Serious Case Review would be “speculative” and beyond scope.
However, the minister said she was committed to a separate review of the Creswell case to examine if there had been opportunities to refer him into the risk management arrangements. She has also instigated a general review of the referral process.
Ms Long said she recognised that there “may have been points at which Jonathan Creswell could have been referred into PPANI for management under those arrangements”.
“It is vital that we fully understand the circumstances and take account of any learning around the management of serious offenders,” she added.
“I have therefore commissioned the independent Lay Advisers, who are appointed by statute to oversee and monitor PPANI, to review the general robustness and operation of the referral process.
“I am also committed to a specific review of the Creswell case.
“This review is intended to establish when he came into contact with any of the PPANI agencies; if there were opportunities to refer him into the arrangements; and to identify learning.
“The review will also consider those points which have been raised in correspondence to my department and to the PPANI co-ordinator.
“The full terms of reference are being finalised and it is my intention to appoint an independent reviewer to undertake this work.”
Ms McAllister welcomed the minister’s undertaking.
“I have been consistently clear the serious failings in relation to Jonathan Creswell must be uncovered and so I welcome this confirmation from the Justice Minister,” she said.
“I am glad the urgent need to review potential failures was taken seriously.
“Creswell had a violent history and a criminal record which reflected this.”
Ms McAllister said there was evidence that indicated that opportunities were missed by the PSNI and that PPANI arrangements should have been in place to manage Creswell.
In regard to the investigation into Ms Simpson’s death, police in Northern Ireland have apologised to her family after a watchdog found their initial probe was flawed.
The Police Ombudsman last year concluded the the PSNI had “failed” Ms Simpson’s family and criticised a “lack of investigative mindset”.