Police say they have now identified 637 young people who were in the queue or car park at the Greenvale Hotel in Cookstown on St Patrick's Night.
Morgan Barnard, 17, Lauren Bullock, 17, and Connor Currie, 16, died after a crush outside the hotel.
The PSNI has again appealed for witnesses to come forward.
"We want to be satisfied that there are no other witnesses who we have not identified," said Det Sup Richard Campbell.
"I would again reassure anyone with concerns that it is not our intention to pursue any young people in relation to entering or trying to enter the licensed premises.
"This has been agreed with the PPS. The focus of the investigation is to try to find answers for the families of the three teenagers who tragically died."
People will be able to speak to police officers at the Burnavon Arts Centre in Cookstown from 15:00 to 20:00 BST on Thursday.
On 24 and 25 April, they will be at the Ranfurly House Arts Centre in Dungannon from 13:00 to 20:00 BST.
"If you're under 18 and coming along can we ask that you do so with your parents knowledge and you'll need to be accompanied by an adult," said Det Sup Richard Campbell.
"Members of health and social care organisations will also be there to provide advice and support to anyone affected by the tragic events."
Two men, including the hotel owner Michael McElhatton, were arrested last month on suspicion of manslaughter.
Both were released on bail.