A man on trial in Lebanon accused of murdering two Irish soldiers 38 years ago has recently been convicted of a charge of collaboration with Israel, it has emerged.

RTÉ News has learned that the Department of Defence was unaware of the conviction of Mahmoud Bazzi for collaborating with Israel until given the news by the bereaved families of Private Derek Smallhorne and Private Thomas Barrett.

The Smallhorne family in Dublin and the Barrett family in Cork have been campaigning for justice for their murdered loved ones for decades.

Both men were abducted at gunpoint and shot dead when a United Nations convoy was attacked in April 1980.

The families learned from a source in Beirut that the man currently charged with the murders - Bazzi - was recently found guilty of collaboration with Israel and given a five-year prison sentence with hard labour.

It is understood that after being informed of the news by the Smallhorne and Barrett families, it took a further six days for the Department of Defence to separately confirm the news through official channels in Lebanon.

Both bereaved families have now communicated to the department their deep upset and frustration at finding themselves in a position where they were informing the Department of Defence about an update in the case, rather than the other way around.

In a statement to RTÉ News, the Department of Defence said the decision to convict Bazzi of collaboration was not made at a public sitting of the Military Tribunal in Beirut.

"The department understands this decision was arrived at by the tribunal meeting in closed session following conclusion of the public sessions and there was no prior notice by the tribunal to this effect."

The department added that once notified by the families of the development, it had pursued the matter through Ireland’s representative in Lebanon.

"The department asked that a meeting be held at the most senior level with Lebanese authorities so we could provide as much information as possible to the families."

Subsequently, in correspondence with the Smallhorne and Barrett families, a senior official in the Department of Defence said Lebanese officials had not advised Irish officials of the conviction of Bazzi for collaboration with Israel as "they saw this as essentially an internal matter for Lebanon and from their perspective this was not the primary issue in the case we were seeking to have prosecuted".

The official told the families "it is unfortunate we did not receive the information at the time of the verdict and I regret any anxiety you have been caused as a result ... we have asked our interlocutors to keep in close contact with the authorities on all matters relating to Bazzi".

The Military Tribunal will sit again at the end of June to hear further evidence in relation to the murder charges.

It is expected the court will hear from four witnesses who knew Bazzi in 1980 and who have confirmed his military status, and have previously linked him to the crimes in old testimonies.

The case against Bazzi of murdering Smallhorne and Barrett, and of attempting to murder their colleague Private John O'Mahony, is based on a number of eyewitnesses to the events that unfolded in broad daylight in April 1980 near the village of Bint Jubayl in south Lebanon, close to the Israeli border.

Mahmoud Bazzi was deported from the US in 2015

The case began in 2015 after Bazzi was deported from the US where he had been living since the 1980s.

Bazzi had always been a suspect in the murders of Smallhorne and Barrett, but for almost two decades his whereabouts were unknown after he fled Lebanon.

Despite RTÉ’s Prime Time exposing the fact that Bazzi was living openly in Michigan in 2000, it took another 15 years before he was deported back to Lebanon in January 2015, where he was taken into custody to await trial on the charges of murder and attempted murder.

Watch the Prime Time report here

News of his deportation from the US was welcomed at the time by the Smallhorne and Barrett familes, and by the Justice for Smallhorne and Barrett group, made up of many former comrades of the murdered soldiers.

Funeral of Private Smallhorne who was killed in 1980
Privates Barrett and Smallhorne were on peacekeeping duty in Lebanon

In November 2015, now retired soldier John O'Mahony travelled from his home in Co Kerry to Beirut to give eyewitness testimony, stating that Bazzi was the man who shot him at point blank range in April 1980.

RTÉ Prime Time travelled to Beirut at that time; attended the court and witnessed Mr O’Mahony stand just metres away from Bazzi and say "I’m 100% certain that man shot me".

It is alleged that a short time after Mr O’Mahony was shot close to the Israeli border, his two colleagues - Smallhorne and Barrett - were abducted, driven away and shot dead in an attack committed by the self-styled South Lebanon Army (SLA), which was an Israeli-backed Christian militia.

John O'Mahony said he was shot and wounded by Mahmoud Bazzi

The trial of Bazzi has been held intermittently over the last three years, and he has remained in custody as the trial is ongoing. The case is being heard before a Military Court in Beirut.

While the recent decision by the court finding Bazzi guilty of collaboration with Israel was not made in public, the families of the Derek Smallhorne and Thomas Barrett, who were both fathers of three children, are incensed that the Irish Government was completely in the dark about a development in the case.

The trial of Bazzi on the charges of murdering Privates Smallhorne and Barrett and attempting to murder Mr O’Mahony continues, with the case due back for hearing again at the end of June.

In March, Minister of State at the Department of Defence Paul Kehoe travelled to Lebanon and met Lebanese Minister for Defence and the Commander in Chief of the Lebanese Armed Forces.

The statement issued to RTÉ said that Minister Kehoe had used his meetings with Lebanese officials to "convey the clear and unambiguous position of the Irish Government that every effort is made to secure justice for the Barrett and Smallhorne families".