The police have sent a “substantial” file to the Public Prosecution Service relating to the deaths of three teenagers in a crush outside a Cookstown hotel disco last year.
They say it marks “a significant milestone” in their investigation.
Lauren Bullock, 17, Morgan Barnard, 17, and 16-year-old Connor Currie died outside the Greenvale Hotel on 17 March, 2019.
Some 800 young people were at the venue at the time.
The owner of the hotel, Michael McElhatton, was one of those questioned by police following the tragedy.
Det Sup Richard Campbell said the interim file contained a substantial amount of material, and that more documentation would be sent to the PPS in the coming months.
“Our focus remains firmly on trying to find answers for the grieving families of the three teenagers and we remain in close, regular contact with them to provide updates on the progress of the investigation, including the submission of the interim file,” he said.
The “complex” investigation was one of the largest ever undertaken by the PSNI.
Police previously disclosed they had identified more than 1,000 witnesses.
Separately, the Police Ombudsman has interviewed seven officers in connection events on the night of the crush.
Marie Anderson’s office launched an investigation after it emerged the first officers to arrive at the Greenvale Hotel withdrew to await support.