In other words, the “postulados” are the demobilized fighters and applicants for benefits under the Colombian Peace and Justice Law of 2005 (see please first link of The Center for Justice and Accountability below). To understand the idea of “postulados” one needs to know what the Colombian Justice and Peace Law (official name is Law 975 of 2005) means. This Law sets the legal framework to ease the demobilization of paramilitaries and also the guerrilla groups in the country.

The final decision whether the candidates are eligible or not for the benefits corresponds to the Colombian Ministry of Justice (see second link).

This link explains the legal process in full:
https://cja.org/where-we-work/colombia/related-resources/col...
Applicants for benefits under the Justice and Peace Law must offer versiones libres, or voluntary depositions, in which applicants freely confess all crimes committed. Voluntary depositions are taken in two sessions. First, the demobilized fighter presents his or her version of the facts, including the date, place, motive, other perpetrators or participants, the victims, and any other information that will clarify the crimes that he or she committed as a member of an illegally armed group, as well as to indicate all illegally gained property and goods, which are to be delivered to the Reparation Fund.
n the second session, a prosecutor interrogates the applicant to extract more information. At this stage, victims or their representatives and the public attorney may request clarifications or verifications of facts, present evidence, and report anything relevant to the conduct in question. After making a statement, the demobilized fighter is brought before a judge to ensure that he or she is formally charged within 36 hours. [13]

Here you will find the “oficial” definition of the term:
https://www.fiscalia.gov.co/colombia/justicia-transicional-2...
Consulta postulados
Postulados
El carácter especial del proceso de Justicia y Paz reglado por la Ley 975 de 2005 (reformada por la Ley 1592 de 2012) implica que su inicio tiene lugar en la remisión de la “lista de postulados” mediante la cual el Ministerio de Justicia presenta como elegibles al procedimiento y a los beneficios establecidos en dicha ley a las personas que hayan pertenecido a un grupo armado organizado al margen de la ley (GAOML), que hayan decidido desmovilizarse de manera individual o colectiva y hayan solicitado su postulación.

Spanish term (edited): (Col) postulado

Perhaps a euphemism for a political-prisoner defendant - echoes of PM Maggie T's war on the IRA and the 'dirty protest.'

In this case, I think the US Am. term of a criminal confederate is the idea.

Proceso de paz: justice of the peace : Magistrates' Court-level in E&W (parties: prosecution vs. defendant or accused : used interchangeably, albeit questionably cf. a defendant of a private prosecution, in ENG law of evidence textbooks) and Sheriff Court in Scotland (Lord Advocate vs. accused / defender is a civil party).

'Colombia’s transitional justice has a seemingly clear mission, to prosecute former members of the FARC and of the military who committed war crimes during the 52-year-long conflict. But another party keeps popping up every now and then, giving the Special Jurisdiction for Peace recurring headaches: the paramilitaries.'