At the age of 20, O’Hanlon is killed on January 1, 1957, along with Seán South while taking part in an attack on the Royal Ulster Constabulary barracks in Brookeborough, County Fermanagh, during the border campaign. Several other IRA members are wounded in the botched attack. The IRA flees the scene in a dumper truck. They abandon it near the border. They leave South and O’Hanlon, both then unconscious, in a cow byre, and crossed into the Republic of Ireland on foot for help for their comrades. The wounded IRA men are treated as “car crash victims” by sympathetic staff in the Mater Misericordiae Hospital in Dublin.
O’Hanlon’s mother remains firmly committed to the IRA and is hurt by the suggestion that there was an alternative to IRA activity or that her son was anything other than an Irish hero.
A marble monument now stands at the spot where South and O’Hanlon lost their lives. An annual lecture has been held in memory of O’Hanlon since 1982, and approximately 500 people attended a 50th commemoration of the men’s deaths in January 2007 in Limerick.
In 1971, a monument is unveiled to O’Hanlon in his hometown on a hill overlooking the Clones Road on which he had made his last journey home. A Gaelic football team is founded in Monaghan in 2003 and called the Fergal O’Hanlons.
On March 14, 1981, a detachment of the British Army surrounds a farmhouse near Rosslea, containing McElwaine and three other IRA members. Despite being armed with four rifles, including an Armalite, the IRA members surrender and are arrested. While on remand in Crumlin Road Gaol, McElwaine stands in the February 1982 Irish general election as an independent candidate for Cavan–Monaghan and receives 3,974 votes (6.84% of the vote). In May 1982 he is convicted of murdering the RUC and UDR members, with the judge describing him as a “dangerous killer” and recommending he spend at least 30 years in prison.
On September 25, 1983, McElwaine is involved in the Maze Prison escape, the largest break-out of prisoners in Europe since World War II and in British prison history. Thirty-eight republican prisoners, armed with six handguns, hijack a prison meals lorry and smash their way out of the prison. After the escape McElwaine joins an IRA Active Service Unit operating in the area of the border between Counties Monaghan and Fermanagh. The unit targets police and military patrols with gun and bomb attacks, while sleeping rough in barns and outhouses to avoid capture.
On April 26, 1986, McElwaine and another IRA member, Seán Lynch, are preparing to ambush a British Army patrol near Rosslea, County Fermanagh when they are ambushed themselves by a detachment from the Special Air Service Regiment. Both are wounded but Lynch manages to crawl away. A January 1993 inquest jury returns a verdict that McElwaine had been unlawfully killed. The jury rules the soldiers had opened fire without giving him a chance to surrender, and that he was shot dead five minutes after being wounded. The Director of Public Prosecutions requests a full report on the inquest from the RUC, but no one has been prosecuted for McElwaine’s death.
McElwaine is buried in Scotstown, with his funeral attended by an estimated 3,000 people, including Gerry Adams and Martin McGuinness. McGuinness gives an oration describing McElwaine as “a brave intelligent soldier, a young man who gave up his youth to fight for the freedom of his country” and “an Irish freedom fighter murdered by British terrorists.”
On April 1, 1990 a monument to McElwaine is erected in Corlat, County Monaghan. The oration is given by a Catholic priest, Father Piaras Ó Dúill, who compares McElwaine to Nelson Mandela, saying they both had the same attitude to oppression and both refused to denounce principle. The inscription on the monument is a quote from Patrick Pearse: “As long as Ireland is unfree the only honourable attitude for Irishmen and Irishwomen is an attitude of revolt.” A monument to McElwaine and six other republicans is erected in Rosslea in 1998, and unveiled by veteran republican Joe Cahill.