The Police Ombudsman in the North is to investigate the actions of the first officers to attend a crush in Co Tyrone.
Three teenagers lost their lives in the tragedy at the Greenvale Hotel in Cookstown on St Patrick's night.
17-year-old Lauren Bullock died at the scene.
Morgan Barnard, also aged 17, and 16-year-old Connor Currie died after being brought to hospital.
A PSNI investigation into the incident is "active and wide ranging".
In a statement today, police in the North said it's "right and proper" that the actions of all those involved are examined.
They say that the first officers to attend "withdrew to await further police support" following an initial assessment of the scene.
The statement explains: "When the first ambulance arrived police moved forward in support of them."
According to the force, the "timing and nature of police actions" now need further investigation.
It adds: "The Chief Constable has therefore decided that the initial police response should be subject to independent scrutiny and it is in the public interest to refer the circumstances and the nature of the actions of the first officers arriving at the scene to the Police Ombudsman."
Families of the victims have been informed of the referral, the statement adds.