LONDON -- The young guerrillas walked unnoticed past the lone Austrian policemen into the OPEC offices in Vienna in December 1975.


Minutes later a burst of gunfire marked the start of an attack that made Carlos notorious.


I saw Carlos go in, but of course I did not know who he was.


The next time I saw him, he was brandishing a sub-machine gun.


It was a Sunday morning and it was a relatively routine meeting of the Organization of Petroleum Exporting Countries oil ministers.


We did not expect a great deal out of the meeting.


As it was a Sunday morning, I thought I would go down without bothering anyone else on the staff and hang around for a bit.


Shortly after I took up my post in the lobby together with another journalist, a group of rather odd-looking characters came through the front entrance and walked up the stairs.


This was not very unusual because OPEC at this time had 11 members and all kinds of people came in and out of the building.


The only odd thing was that one of them, I think it was Carlos, was carrying a sports bag.


There was one solitary, rather elderly and stout, Austrian policeman standing outside.


A few minutes later we heard gunfire and we rushed upstairs.


We went into the door of the OPEC office, and that is when we got our first glimpse of these people with their guns.


They were not firing, but we decided it was wise thing to get out.


There was no way of filing a story from the OPEC office.


So I went to a public telephone box and had to persuade a rather irate lady who was talking to her nephew to leave.


I explained to her that there was a major incident and I was a journalist and so had to report it.


The story was filed to the Vienna office and I think we had a very clear beat on it.


But for a long time we did not really know that Carlos was involved.


We had no idea who these people were and we had no way of making contact without endangering our lives.


The six guerrillas shot three people to death and wounded seven others in the raid on December 21, 1975.


They seized 81 hostages, including 11 OPEC ministers.


After freeing all 41 Austrian hostages, they flew to Algeria on a commandeered Austrian DC-9 jetliner a day later.


They released some of the other prisoners on arriving in Algiers, turned over several more captives after a stopover in Tripoli, Libya and returned on December 23 to Algiers, where the remaining hostages were set free.


The five men and a woman surrendered to Algerian authorities.


They were allowed to go free within a few days.