The survivor of a 2005 knife attack that resulted in the death of his friend and garnered international attention, including from the White House, has spoken publicly about his guilt and the unsolved nature of the crime. Brendan Devine detailed his experiences for the first time on television in a new BBC documentary series, "Murder in Belfast: Sisters Seeking Justice."

Devine sustained a slashed throat and a stab wound to the abdomen during the attack that killed his friend, Robert McCartney. The incident occurred after the two men left Magennis's bar in Belfast city center. McCartney, who was 33 and a father of two, was engaged to be married. Despite an estimated 70 people being present in the bar, no witnesses came forward to identify the assailants. CCTV footage from the pub was destroyed, and some forensic evidence appears to have been compromised.

The Provisional IRA initially denied involvement but later stated that three of its members were involved, including two high-ranking operatives, and that they had been expelled. The murder occurred during a sensitive period in the Northern Ireland peace process, with the IRA observing a ceasefire while facing accusations of other high-profile robberies, including a significant theft from the Northern Bank.

McCartney's family launched an extensive campaign for justice, which gained support from international figures, including U.S. President George W. Bush, who invited the sisters to meet him in Washington D.C.

Devine expressed deep-seated guilt over his role in the events, specifically believing that his actions and words outside the bar may have escalated the situation. "I don't feel guilty for the actual happening but I do worry that my big mouth could have inflamed the situation, and got Bert killed," he stated. "That kills me."

He recounted an incident where he asked about "Jock Davison," a figure he identified as a senior IRA leader in Belfast. Devine believes this question led to the attackers confronting him. Davison was later killed in a gun attack in Belfast in 2015.

Devine also revealed that he was questioned by the IRA as part of a parallel investigation to the police inquiry. He stated that he only fully cooperated with the police after receiving clearance from the IRA. In 2008, three men were tried in connection with the killing, but all were acquitted.

Devine testified at the trial, but his account of the night's events reportedly changed. He denied claims that his testimony was intended to align with another witness's account. He also received numerous death threats, contributing to significant stress and impacting his mental health, leading to a diagnosis of post-traumatic stress disorder.

The documentary series, produced by BBC Northern Ireland in association with RTÉ, explores the murder and the McCartney family's persistent pursuit of justice, highlighting Devine's enduring struggle with the unresolved nature of the crime and its personal impact.

Robert McCartney, a father of two, was planning to marry his partner Bridgeen Hagans

Brendan Devine was diagnosed with post-traumatic stress disorder after his friend was killed

McCartney died after being beaten and stabbed outside the pub in Belfast city centre in January 2005