The initial police response to the incident at a County Tyrone hotel in which three teenagers died is to be investigated by the Police Ombudsman.
It has been revealed that the first officers who arrived at the scene of the tragedy withdrew to await support.
Morgan Barnard, 17, Lauren Bullock, 17, and Connor Currie, 16, died after a crush at the Greenvale Hotel in Cookstown on 17 March.
Hundreds of young people were queuing to get into the St Patrick's Day disco.
The first police officers arrived at the hotel grounds shortly after receiving a 999 call.
"Following their initial assessment they made attempts to establish more detail and information about what was happening and subsequently withdrew to await further police support," said Deputy Chief Constable Stephen Martin.
"When the first ambulance arrived police moved forward in support of them.
"The timing and nature of police actions during this period require further investigation to fully establish the facts.
"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."
The funerals of the three teenagers were held in Cookstown on Friday.
Two men, including the hotel owner Michael McElhatton, were arrested last week on suspicion of manslaughter.
Both have since been released on bail.
"The confidence of the families and the confidence of the communities we serve are at the forefront of our minds in our decision to refer this matter to the Police Ombudsman," Dep Ch Con Martin said.
"We will work with the ombudsman to support whatever action he undertakes and would ask that people do not speculate or prejudge the outcome of the ombudsman's investigation."
The Police Ombudsman has appealed for witnesses to contact them via email at firstname.lastname@example.org.