Two senior gardaí are due to travel to South America today as part of their efforts to build a case against the so-called Colombia Three.
Niall Connolly, Martin McCauley and James Monaghan are currently on the run from Colombian justice after being convicted of training anti-government rebels in the country.
They recently returned to Ireland and turned themselves into the Gardaí before being released without charge.
Experts believe they are unlikely to be sent back to Colombia due to the lack of an extradition treaty with Ireland and the South American country's poor human rights record.
However, there have been suggestions that they could be made serve their 17-year sentences in Ireland.
Minister for Justice Michael McDowell has vowed that all option will be vigorously pursued.