Three Irishmen detained in Colombia last August were formally charged this weekend with training left-wing rebels in bomb-making skills.
After a lengthy investigation, the case against Mr Niall Connolly, Mr James Monaghan and Mr Martin McCauley was sent to a federal judge on Friday, according to Ms Carolina Sanchez, spokeswoman for Colombia's attorney general's office. The trial could begin as early as next month.
Colombia's state prosecutor has charged the three men with teaching bomb-making skills to members of FARC, Colombia's Revolutionary Armed Forces, an organisation which has been at war with the government for the past 40 years.
They were initially arrested for travelling on false passports, a minor infringement which usually results in deportation. However, they now face up to eight years in jail if convicted of the bomb-making charges. The three were detained at Bogota airport last August after leaving a demilitarised zone ceded to FARC rebels as an incentive to join peace talks.
"The case has been plagued with irregularities from the moment the men were arrested," said Ms Caitríona Ruane, a spokeswoman for the Bring Them Home Campaign. "The latest news was leaked to the media before either the three men or their lawyers were informed. The prosecutors ignored our witnesses, they ignored forensic evidence and prevented us from visiting the FARC zone to talk to witnesses."
Ms Ruane recently visited Colombia with Fianna Fáil TD Mr David Andrews, who expressed doubts at the prospect of the men getting a fair trial in the prevailing political circumstances.
The three men will appeal the decision, challenging the impartiality of the prosecutor in charge of the case. Under Colombian law, this final appeal will be heard by a judge who then decides if the case should go forward for trial.
The men have denied the allegations and a campaign on their behalf has lobbied politicians and press to reconsider the case. The defence campaign took out a full-page advertisement in Colombia's conservative daily El Tiempo last month but its concerns have fallen on deaf ears, as Colombians rally to hardline candidates in upcoming presidential elections.
The FARC is currently engaged in ceasefire talks but continues to attack remote villages and destroy power pylons. The Irishmen claimed they were passing on information about the Irish peace process to the rebels and that the arrests formed part of a campaign to undermine peace talks between the government and FARC rebels.
"The men are innocent," said Mr Agustin Jimenez, a human rights lawyer working on their behalf. "The case has been flawed at every turn."
The prosecutor's main witness is a former driver for a FARC commander, who turned informer and testified that he had seen the three men visit the demilitarised zone on several occasions. He also said he had received instruction from them on building pipe bombs and working with dynamite.
The defence campaign has called on the Irish Government and international human rights agencies to "urgently intervene".