...that Jose Obdulio Gaviria and Francisco Santos, both former Uribe administration officials, are being prosecuted for statements that slandered union workers back in 2007.
Basically, the unionists attended a left-wing seminar in Quito and these two men practically accused them of being terrorists or FARC members because of a declaration released at the end of the event, which included a general statement of support for "the insurgent movement in Colombia" and, in another paragraph, also endorsed "all forms of struggle" by praising the "organized violence of the masses" as the only method that will bring about the final defeat of bourgeoise imperialism. This last part was a generic argument, by the way, and not talking about any concrete situation.
You can read the entire declaration here (in Spanish):
http://www.voltairenet.org/XI-Seminario-InternacionalBoth FARC and ELN, though apparently they didn't openly participate in the event, are included among the list of participants at the end of the document. I imagine they either went there in secret or otherwise expressed their support through e-mail or other means.
The Colombian unionists themselves say they didn't actually sign any declaration and had left Quito two days earlier, according to their plane tickets, which is why they later requested that the names of their union organizations should be removed from the list of participants found in that document. As you can see, the current version of the text doesn't include them.
After the comments by Gaviria and Santos, which criticized and insulted the workers, they were threatened by paramilitaries from the Black Eagles. As a result, the unions have denounced that such actions have put them in danger and also formally accused Gaviria and Santos of slander.
Now, the defense is apparently resorting to delays in order to either slow the case down to a crawl or make the legal terms expire.