Collusion between the security forces and loyalist paramilitaries reached systematic levels during some of the worst years of Troubles, a new book has claimed.
A number of then serving police officers and soldiers were part of a loyalist gang whose members were responsible for 120 murders between 1972 and 1976, according to the authors of Lethal Allies - British Collusion in Ireland.
They claim the alleged new evidence of co-operation between the police, army and loyalists further emphasises the need for a truth recovery process in Northern Ireland.
Produced by the Pat Finucane Centre in Belfast, the book focuses on 120 killings attributed to the loyalist grouping between 1972 and 1976 in the Mid Ulster area and in Irish border regions.
It draws on investigation reports compiled by the specialist police unit re-examining Troubles' deaths - the Historical Enquiries Team (HET).
Among attacks examined in the book is the UVF Step Inn pub bombing in Keady in August 1976, which claimed the lives of two Catholics - mother of three Elizabeth McDonald, 38, and 22-year-old Gerard McGleenan.
The book alleges that Royal Ulster Constabulary Special Branch was aware of the planned car bomb attack ten days before the incident but failed to move in.
The period covered by the book covers one of the darkest periods of the Troubles.
The IRA were also responsible for numerous murderous attacks across the time-span, including the Bloody Friday bombings in Belfast in 1972 and the Kingsmill massacre of ten Protestant workmen in 1976.