The first police officers at a deadly crush in Cookstown “acted in good faith”, a chief constable said.
Lauren Bullock, 17, Morgan Barnard, 17, and 16-year-old Connor Currie died near the Greenvale Hotel in Cookstown, Co Tyrone, on St Patrick’s Night last month.
Police arrived at the Greenvale Hotel grounds shortly after receiving a 999 report.
Following their initial assessment they made attempts to establish more detail and information about what was happening and withdrew to await further support, police have disclosed.
Police Service of Northern Ireland (PSNI) Chief Constable George Hamilton said the initial officers were “brave” but “there are some questions to answer”.
“I think that delay and the justification for it deserves some answers and some accountability.
“That is without prejudice to the officers, who it seems to me acted in good faith.”
The actions of four officers are being investigated by the independent Police Ombudsman, Mr Hamilton said.
He said investigators had done a good job as he discussed the probe more generally.
“The organisation I am responsible for, as far as I am concerned, is competent in this matter.
“The investigation team and local police have done a good job, not to be self-congratulatory in such tragic circumstances.
“It is a human endeavour and sometimes judgments are not quite right.”
Mr Hamilton addressed his Policing Board scrutiny committee in Belfast.
The owner of the Greenvale, Michael McElhatton, identified himself as one of those arrested and later released on suspicion of manslaughter.
He accused police of trying to “blacken” his name over swiftly dispelled drugs suspicions after officers searched his home and found unidentified powder.
Mr Hamilton acknowledged the episode did not look good.
He said: “It is regrettable that it took the attention away from the investigation for a few days.
“For me, that distraction regarding the drugs arrest and de-arrest was exactly that.
“The officers who carried out the arrest did so on the basis of having the reasonable suspicion required.
“That was all done appropriately and we certainly would not have been putting out the identity of anyone arrested prior to charge in the courts.”
Police have identified hundreds of witnesses to the teenagers’ deaths.
The area outside the hotel was packed with young people dropped off by buses just before the popular nightspot opened.
Investigators said teenagers were trodden underfoot during the crush near the entrance to the disco.
The head of the Catholic Church in Ireland said the area had become a “valley of tears” following the tragedies.
Three back-to-back funerals were held in the Dungannon area and were attended by large numbers of mourners.