By Fergal Keane BBC Correspondent in Colombia

I slept next to the brothel.

The music and shrieks from that sad bordello drifted in the window until long past dawn, while I turned and sweated in the muggy swamp of my bed, the main attraction for squadrons of mosquitoes.

But I had some consolation. I was not the most uncomfortable Irishman in Colombia that night.

The notion of convicted terrorists James Monaghan and Martin McCauley chasing butterflies in the jungle is charming - but am I alone in wondering if it is true?

Far away in a high-security prison, three Irish Republican prisoners were enduring another night of captivity.

They are suspected to have trained the Colombian extreme left-wing FARC rebel group in terrorism techniques.

This week, a congressional report released in Washington alleged that links exist between the FARC and the Irish Republican Army - the IRA quickly denied that any of its operatives had been sent to Colombia to carry out training.

Safe haven

I was, in fact, following a path those same Irishmen had blazed some months before.

For all I knew, they may even have stayed in the same hotel in San Vicente, the town in the Colombian jungle which until recently was the capital of the guerrilla safe haven.

Under a unique arrangement, the government had allowed the Marxist guerrillas of FARC to control a vast swath of territory, on condition that they were good chaps, and talked about a ceasefire.

They did talk, and talk.

Alas, they also kidnapped and killed, and continued to raise millions from taxing the cocaine which flourishes in the jungles of Colombia.

The FARC are the world's richest Marxists. The US government believes they earn as much as US$300m a year from the drugs trade.

Guerrilla needlework

The following morning, I set out for the big FARC base in the hills outside San Vicente.

The inquiry was launched after the arrest of three alleged terrorist trainers

One of the group's leaders had agreed to an interview, news delivered to me by a bearded, motorbike-riding revolutionary with whom I dined the night before.

The guerrilla camp was a muddle. The commandant would be with us in a few minutes, a young guerrilla guard had announced - we should be patient.

The teenage fighter was polite, but she was preoccupied.

We had interrupted her morning needlework session. She had been busy stitching a holster for her pistol.

It was a scene of extraordinary incongruity. The Women's Institute meets Che Guevara.

Cautious response

Commandant Raoul Rais turned out to be a very dreary man - plump, and dressed in immaculate fatigues, he sat with an armalite in his lap throughout the interview.

They came here for one reason only - to share political views

Commandant Raoul Rais

The FARC is the people, so any American threat to us is a threat to the people, he droned.

But the commandant was very cautious when I brought up the question of the three detained Irishmen.

They came here for one reason only, to share political views.

They wanted to study the peace process in Colombia, and to share with us about the peace process in Ireland. And that was that.

The US State Department, though, believes otherwise.

One of its officials told congress it was his information that the three had traces of explosives on their clothes.

They had also been travelling on false passports. And the FARC had of late been using bombing tactics familiar to anybody who had studied the IRA in Northern Ireland.

The White House seems disinclined to accept that the men were on a mission of peace.

Rather, it believes they were training a group which has threatened American lives, and which is now a target of the war on terror.

Eco-tourists?

Why would three Irish Republicans go to one of the most dangerous countries on earth, travelling on false passports, into the stronghold of a guerrilla group notorious for kidnapping, drug trafficking and murder?

It is a question the three defendants will attempt to answer at their trial in Colombia, but one which has caused untold embarrassment for Sinn Fein, and considerable anger for the White House.

The arrests have caused embarrassment for Sinn Fein

There may indeed be a simple explanation.

They might have been there as eco-tourists, the first explanation offered, or to study the Colombian peace process - the subsequent explanation.

The notion of convicted terrorists James Monaghan and Martin McCauley chasing butterflies in the jungle or listening to the warbling of parrots is charming. But am I alone in wondering if it is true?

For all that, I doubt that Mr Bush will want action against Sinn Fein that might in turn precipitate a crisis in the Irish peace process.

There is, it needs to be said, no proof that the party, or indeed, the IRA, sent the men to Colombia.

Big American stick

And with the Middle East in flames, the last thing the White House needs is trouble in a place where the US has gained so much credit for its peacemaking role.

There already have been some very tough words in private, but my guess is it will not go much further than that.

As far as the commandant and his comrades are concerned, stand by not for words, but for a very big American stick.

In George W Bush's world of friends and enemies, the commandant knows exactly where he stands.