A new file on the Enniskillen bombing is to be handed over to police.
The report from the Historical Enquiries Team (HET) will be examined by serious crime branch detectives who will determine whether any fresh criminal proceedings can be taken against the perpetrators of the IRA atrocity 25 years ago.
DUP MLA Arlene Foster said: "The Enniskillen bomb was an act of horrific savagery. It was motivated by nothing other than a desire to kill and maim. It was indiscriminate. Young and old were injured. It was targeting innocent people."
Eleven people were killed and 63 others were injured when the no warning bomb ripped through the Co Fermanagh town on November 8, 1987. A twelfth victim, school principal Ronnie Hill, spent 13 years in a coma and died in 2000.
No one has ever been convicted in connection with the massacre which was deemed among the worst of the Troubles. Thursday marks the 25th anniversary of the bombing and a special memorial service is being held for the survivors and relatives of those who were killed.
Ms Foster added: "Twenty-five years after the explosion, someone somewhere knows something about the perpetrators. Someone knows where the bomb was made, how it was transported and who planned the attack. This wasn't executed by one of two people. A team of people were involved."
Ms Foster said a breakthrough in the investigation would provide hope for the families seeking justice.
She added: "As has been demonstrated with Gerry McGeough being convicted of the attempted murder of my colleague councillor Sammy Brush decades after the event, there is always time for justice.
"Anyone who can bring any information to the police should do so. Perhaps in 1987 they didn't feel able but as they watch the victims and relatives on Thursday I hope they will be moved to help the police with the investigation."
In a statement the PSNI said: "The Historical Enquiries Team has concluded its work on the deaths which were caused at the Enniskillen cenotaph bombing in 1987. Staff have updated the families on the HET work and will formally hand over to the PSNI's serious crime branch who will assess the potential for further work to be progressed."