As a member of the UVF's Mid-Ulster Brigade led by Robin "the Jackal" Jackson, Weir was a part of the Glenanne gang, a group of loyalist extremists that carried out sectarian attacks mainly in the County Armagh area in the mid-1970s.
Weir and his RUC colleague Billy McCaughey were convicted of the 1977 sectarian killing of Catholic chemist William Strathearn and sentenced to life imprisonment.
Weir's affidavit which implicated Jackson, other members of the Glenanne gang, soldiers of the Ulster Defence Regiment (UDR), and his colleagues in the RUC and SPG, in a series of sectarian attacks, including the Dublin and Monaghan bombings, was published in the 2003 Barron Report, the findings of an official investigation into the 1974 car bombings commissioned by Irish Supreme Court Justice Henry Barron.
[2] Over six feet tall, powerfully built, with blond hair and blue eyes, he had an imposing physical presence, which made him stand out in a crowd.
[4] His duties involved making early morning arrests, evacuation of civilians at the scenes of suspect bombs and responding to explosions and shootings, as well as riot control.
Weir stated he first met senior UVF member Robin Jackson in a pub in Moira, County Down, in 1974 where he had gone to have drinks with his girlfriend.
According to his later account of events leading up to the attack, when he arrived at Mitchell's farm the designated evening, he saw between eight and ten men dressed in camouflage, parading in the farmyard.
Weir took his first active role as a UVF paramilitary in the attempted bombing attack against Renaghan's Bar in Clontibret, County Monaghan in the Republic of Ireland on 15 August 1976.
The operation was aborted after Weir had driven to Clontibret on the morning of the planned attack to ascertain the roads were clear, only to discover the town had already been sealed off by the Irish Army and Gardaí.
When Weir displayed his RUC warrant card to a Garda officer, he was told the Gardaí had received a tip-off from the Northern Ireland security forces that Clontibret was the target of a proposed bombing that evening.
The next night a UVF unit drove the bomb car, which had been meant for Clontibret, and parked it outside a Catholic owned pub and home in Keady, County Armagh; it exploded, killing a man and a woman.
He began to supply the Mid-Ulster UVF with weapons he procured from a loyalist group in County Down called the "Down Orange Welfare" which comprised both former and serving members of the security forces, including Chief Inspector Harry Breen.
The story that emerged at the trial was that Weir and McCaughey had decided Strathearn should be killed as they erroneously believed him to be a member of the Provisional IRA.
To carry the killing out, they recruited two other loyalists and drove them to Ahoghill where they knocked on the door of Strathearn's home, which was also the village's main shop and chemist, and asked him to open up as they urgently needed medicine for a sick child.
[12] It was also stated during the trial that the two gunmen had been Robin Jackson and his associate Robert John Kerr,[10] while Weir had maintained he and McCaughey had stayed in the car during the killing.
[14]Weir declared: "I think it is important to make it clear that this collusion between loyalist paramilitaries such as Robin Jackson and my RUC colleagues and me was taking place with the full knowledge of my superiors".
In January 1999, to assist journalist Sean McPhilemy, who was being sued for libel, Weir signed an affidavit containing 62 paragraphs in which he outlined in detail the instances of collusion between his RUC and SPG colleagues, members of the UDR, and loyalist paramilitaries such as Robin Jackson.
Stewart Young, a prominent member of the Portadown UVF, told Weir he had headed the team that planted the Monaghan car bomb which had killed an additional seven people 90 minutes after the Dublin blasts.
Weir stated that UDR intelligence officer Captain John Irwin had supplied the explosives,[5] and James Mitchell's farm had been used for the construction and storage of the bombs.
[21] Weir identified Jackson as the gunman in many shootings, including those of Strathern, PIRA volunteer John Francis Green, and three members of the O'Dowd family.
While in prison, Weir wrote a letter to a friend in which he suggested that Jackson had links to British Intelligence Corps and Captain Robert Nairac.
[22] Weir claimed in his statement that shortly before he was sent to Newtownhamilton six months after the Strathearn killing, his association with loyalist paramilitaries became known to senior RUC officers, who encouraged it.
He was summoned to a meeting with Chief Inspector Brian Fitzsimmons,[n 1] head of the RUC Special Branch in Newry, who let Weir know he was aware of his UVF activities.
[citation needed] After his transfer to Newtownhamilton, Weir felt his life was being placed in danger after Intelligence Corps officers also made contact with him regarding proposed attacks against the IRA.
Major Robertson of the Royal Green Jackets suggested he carry out an assassination attempt against Provisional IRA South Armagh Brigade commander Thomas "Slab" Murphy.
[3][5] During this period, the Intelligence Corps and RUC Special Branch were involved in an internal power struggle in their mutual battle against the IRA.
[3] This was when Special Branch decided to put a stop to Weir's activities and he was moved in April 1978 for his own safety to Dunmurry, a quiet suburb on the outskirts of Belfast with little opportunity for collusion with paramilitaries.
[25] In 2004, the human rights group, the Pat Finucane Centre, asked Professor Douglass Cassel (formerly of Northwestern University School of Law) to convene an international panel of inquiry to investigate allegations of collusion in Northern Ireland by the security forces and loyalist paramilitaries in a series of sectarian attacks committed in the 1970s against nationalists.
This panel found Weir's evidence credible and agreed with the Garda Síochána and the Barron Inquiry that his allegations "must be regarded with the utmost seriousness".