Book claims 'indisputable evidence of security forces collusion'
24 October 2013 Last updated at 18:50 BST
A new book claims members of the RUC and UDR were part of a loyalist gang that killed more than 100 people in the 1970s.
The book claims to have uncovered evidence of collusion on a huge scale.
BBC NI home affairs correspondent Vincent Kearney reports.