McElwaine was an active member of the IRA, who became Officer Commanding of the IRA in County Fermanagh by the age of 19. On 5 February 1980, McElwaine killed off-duty Ulster Defence Regiment corporal Aubrey Abercrombie as he drove a tractor in the townland of Drumacabranagher, near Florencecourt. Later that year, on 23 September, McElwaine killed off-duty Royal Ulster Constabulary Reserve Constable Ernest Johnston outside his home in Rosslea. He was suspected of involvement in at least 10 other killings. On 14 March 1981, a detachment of the British Army surrounded a farmhouse near Rosslea, containing McElwaine and three other IRA members. Despite being armed with four rifles, including an Armalite, the IRA members surrendered and were arrested. While on remand in Crumlin Road Gaol McElwaine stood in the February 1982 Irish general election as an independent candidate for Cavan–Monaghan and received 3,974 votes. In May 1982 McElwaine was 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 25 September 1983, McElwaine was involved in the Maze Prison escape, the largest break-out of prisoners in Europe since World War II and in British prison history. 38 republican prisoners, armed with 6 handguns, hijacked a prison meals lorry and smashed their way out of the Maze prison. After the escape he joined an IRA Active Service Unit operating in the area of the border between Counties Monaghan and Fermanagh. The unit targeted police and military patrols with gun and bomb attacks, while sleeping rough in barns and outhouses to avoid capture. He held a meeting with Pádraig McKearney and Jim Lynagh, members of the Provisional IRA East Tyrone Brigade, in which they discussed forming a flying column aimed at destroying police stations to create I.R.A. controlled zones within Northern Ireland. However, this plan never materialised. McKearney and Lynagh were later themselves killed in the Loughgall Ambush.
Death
On 26 April 1986, McElwaine and another IRA member, Sean Lynch, were preparing to ambush a British Army patrol near Rosslea, County Fermanagh when they were ambushed themselves by a detachment from the Special Air Service Regiment. Both were wounded but Lynch managed to crawl away. An inquest jury found that McElwaine was then questioned while incapacitated and shot dead within five minutes. McElwaine's body was buried in Scotstown, his funeral was attended by an estimated 3,000 people, including Gerry Adams and Martin McGuinness; the latter gave 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". In 1987 McElwaine's father, Jimmy, a longtime member of Monaghan County Council, became the chairman of the Séamus McElwain Cumann of Republican Sinn Féin. On 1 April 1990 a monument to McElwaine was erected in Corlat, County Monaghan. The oration was given by a Catholic priest, Father Piaras Ó Dúill, who compared 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 was erected in Rosslea in 1998, and unveiled by veteran republican Joe Cahill. In January 1993 an inquest jury returned a verdict that McElwaine had been unlawfully killed. The jury ruled 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 requested a full report on the inquest from the RUC, but no one has been prosecuted for McElwaine's death. In April 2006 approximately 1,000 people in Roslea paid tribute to McElwaine during the traditional Easter Commemoration to mark the centenary of the Easter Rising. Victims groups and unionist politicians, including Democratic Unionist Party member Arlene Foster, had asked the Parades Commission to ban the parade from the area where McElwaine was killed, describing him as an "evil murderer", but the Commission ruled the commemoration could proceed without any restriction. In Corlat, two weeks later, some 500 people attended the launch of a documentary film about McElwaine, Life and death of an IRA activist, marking the 20th anniversary of his death.
