The Police Ombudsman is to assess the case of a 39-year-old woman who died in Newry while waiting for an ambulance crew to arrive.
The PSNI has advised Marie Anderson about the matter because officers were with Jody Keenan shortly before she died.
Ms Keenan was a classroom assistant who had worked at St Paul's High School in Bessbrook for 10 years.
She died in the early hours of Sunday after collapsing in the Trevor Hill area of Newry, Co Down.
The ambulance service received an emergency call at about 3.15am but the only two available crews in the Southern division area were at Craigavon Area Hospital handing over patients.
Instead, an ambulance was sent from Belfast, 61km (38 miles) away. A second ambulance was then sent from Banbridge.
PSNI officers with a defibrillator were first to arrive on the scene at 3.52am but Ms Keenan died despite attempts to resuscitate her.
Newry, Mourne and Down PSNI district commander Supt Norman Haslett said: "The Office of the Police Ombudsman for Northern Ireland (OPONI) has been advised about this incident and are currently assessing the matter, given police were with Jody shortly before her death.
“We are currently assisting OPONI with their assessment and our thoughts remain firmly at this time with Jody’s family, friends, colleagues and all those affected by this tragic incident.
“Whilst the Police Ombudsman conducts her assessment no further comment will be made.”
The Northern Ireland Ambulance Service (NIAS) has said a serious incident review will be carried out.
On Monday night, the NIAS said it would like to “apologise sincerely and offer our deepest condolences to the family and friends of the patient who passed away in Newry”.
“We recognise how difficult a time this will be for the family and we will be seeking to engage with them directly in the coming days.”
Jarlath Burns, principal at St Paul’s said Ms Keenan was the “kindest, most beautiful person you could ever meet”.
He told the BBC: “She was loved by staff and pupils and parents alike.”
“She was always committed to making a difference to children who had experienced barriers to learning,” Mr Burns said.
“She went way beyond the call of duty.”
A NIAS statement on Tuesday said: “NIAS exists to help people when they need and when our help falls short, we all feel it very personally and deeply.
“However, we recognise that does not compare to the loss being felt by those closest to the patient.” – PA