The Police Ombudsman of Northern Ireland has started an investigation after it emerged Mary Ward had reported to the PSNI that she had been the victim of a violent crime in the weeks prior to her murder.
The 22-year-old was found dead by PSNI officers at her home on Melrose Street in Belfast on 1 October.
In a statement, the ombudsman said they offered their deepest condolences to Ms Ward's family.
It said that following Ms Ward’s murder, they received a referral from the PSNI on Sunday evening.
It said they have completed their initial review and now commenced an independent investigation.
The investigation will focus on the PSNI response to Ms Ward reporting to police that she had been the victim of a violent crime.
In a statement, the PSNI said: "Following extensive investigations by detectives in Serious Crime Branch, a murder investigation has been launched."
A PSNI spokesperson said it is believed that Ms Ward was last seen alive on Wednesday 25 September.
The PSNI said it is keen to speak to anyone who may have seen or been in contact with Ms Ward on or around that date.
PSNI Detective Chief Superintendent Lindsay Fisher said: "Mary Ward is the fourth woman to be murdered in Northern Ireland in just six weeks. This is absolutely appalling.
"Four families have been shattered forever by meaningless violence."
On 18 August, 57-year-old Sophie Watson was found dead at her home in Magherafelt. Andrzej Pajaczkowski, 43, of Ashgrove Park in Magherafelt is before the courts charged with her murder.
On 24 August, Montserrat Martorell, a 65-year-old woman originally from Spain, was found dead in a flat in Derry city after a fire was reported at the property. Ciaran Murray, 28, of Gortfoyle Place in Derry, is accused of her murder.
On 13 September, the body of 43-year-old Rachel Simpson was discovered in a garage beside a house in Belfast. Her son, 21-year-old Nathan Simpson, of Castlereagh Road in Belfast, has been charged with her murder.
Ms Ward's case has also been referred to the Office of the Police Ombudsman, given prior contact between her and the PSNI.
The police service added: "Whilst at this time there is no suggestion of individual criminality or misconduct, we are nonetheless concerned about our organisational response."
