Ira

Even their name is a reference to the IRA's chosen method of punishment for alleged drug dealers during the Troubles.

Last year an inquest found the atrocity, in Kingsmills, was an overtly sectarian attack mounted by the IRA.

An inquest last year found there was no evidence of collusion or state involvement and that the attack was carried out by a unit consisting of at least 12 members of the IRA, pretending to be an Army patrol.

The IRA has never admitted involvement and was supposed to be on ceasefire at the time of the attack.

In 2009, the Real IRA admitted killing Mr Donaldson, who had worked for Sinn Féin.