Assembly members from Sinn Fein and the DUP have accused each other of links to paramilitary killings.
Moving a motion calling for a public inquiry into claims of security force collusion in the killing of more than 400 Catholics, Ms Mary Nelis of Sinn Fein said there had been "a dirty war" in Ireland for the last 30 years.
Amnesty International, the American government and "a host of credible agencies" had accepted the existence of "death squads" operating "under the control of the RUC Special Branch and military intelligence".
Mr Sammy Wilson of the DUP moved an amendment rejecting the motion and praising the work of the security forces. He accused Mr Pat Doherty of Sinn Fein of being a former IRA quartermaster.
Responding to allegations that more Catholics were killed by the IRA during the Troubles than anyone else, Ms Nelis said the French Resistance during the second World War killed more French people than Germans.
She claimed that the names of 500 republicans found in loyalist arms caches recently had come from the security forces.
These claims were rejected as "black propaganda" by Mr Michael McGimpsey. Mr Billy Hutchinson of the PUP said it seemed that many in Sinn Fein wished to believe loyalists were "too thick" to gather their own information.
He conceded that many loyalist paramilitaries had joined the security forces to access arms, training and intelligence, but said republicans had also done this.
Mr Mitchel McLaughlin of Sinn Fein accused DUP members of "tittering" as the murders of Catholics were being discussed and accused them of "denying the undeniable".
Mr Alban Maginness of the SDLP said both the motion and amendment were symptomatic of a selective view which existed in the Assembly.
"This motion in reality is not concerned with the truth but with establishing a version of the truth," he said.
The DUP amendment was passed, and the Sinn Fein motion defeated.