The Mexican government and some survivors of a notorious massacre of Indigenous peoples by paramilitaries will sign an "amicable agreement" that includes an apology and reparations.

But a group backed by the Diocese of San Cristóbal de Las Casas in southern Chiapas state has rejected the agreement. Group members say they want an investigation that gets to the bottom of the 1997 Acteal massacre and holds the intellectual authors and the Mexican state responsible for the atrocity.

The massacre claimed the lives of 45 Tzotzil -- including 21 women and 15 children -- who belonged to a pacifist, Catholic community known as "Las Abejas" (The Bees) -- as they participated in a prayer service just prior to Christmas. Paramilitaries aligned with the then-ruling political party were blamed for the attack. In 2009, the Supreme Court overturned the sentences of 15 suspects, saying they were convicted on faulty evidence.

"What happened here in Acteal cannot be resolved in an amicable way," Antonio Vázquez Gómez, a founder and director of Las Abejas, said in a video statement.

"Las Abejas, all of them, are demanding justice," Dominican Father Gonzalo Ituarte, former diocesan vicar, also said in a video statement. "They're not in favor of the amicable agreement because it implies denying the right to know the truth and that justice is done."

The attack on a pacifist community during prayer and the sheer cruelty -- with the assailants chasing victims through a cloud forest for hours and not even sparing four pregnant women -- highlighted the struggles of Indigenous communities in Chiapas. The lasting impunity showed the difficulties in achieving justice in a country where most crimes -- even the most notorious -- go unpunished.

It also came at a turbulent time as the Zapatista National Liberation Army won worldwide attention for briefly occupying cities in Chiapas, a major embarrassment to the Mexican government.

Representatives of both nongovernmental sides -- who call themselves "Las Abejas," even though the organization has splintered several times since the massacre -- say they want a comprehensive investigation via the Inter-American Commission on Human Rights, to hold the Mexican state accountable. But they deeply disagree on the idea of accepting a "friendly solution."

Patrocinio Hernández Gómez, representative of the group agreeing with the government, said the amicable agreement does not truncate a further investigation.

"The first condition we put (on the table) is going to be fulfilled Sept. 3 ... the Mexican state is going to recognize its responsibility for actions and omissions, and it's going to be an act of public apology to the survivors," he told Catholic News Service.

The agreement was announced July 17 in a brief statement from the Interior Ministry, which said it would allow both sides to "advance together in the reconstruction of the social fabric in Acteal and the surrounding Indigenous communities."

Talks on an amicable agreement between a group of survivors -- which Hernández claims is the majority -- and the government started in 2015. The group entering into the amicable agreement is not giving up on a further investigation, but Hernández said many were motivated by factors such as "not having had medical attention" and seeing survivors pass away as time dragged on.

Hernández responded to a question on the subject of compensation by saying, "Many times we tend to Satanize and (say) 'Well, they're looking for money,' and belittle a proposal from the victims themselves."

Las Abejas was formed in 1992 in response to land seizures and pursued pacifism at a time when armed conflict was stirring in Chiapas.

Like the Zapatistas, Las Abejas live autonomously, meaning they do not participate in government social programs.

Armed conflicts among communities around Acteal have been rife since the massacre, with paramilitaries that committed the attack still residing in the area.

"What we've had is a series of half measures," said Ruben Moreno, director of the Fray Bartolomé de Las Casas Human Rights Center, which represents those not signing the "friendly solution."

"What we want is a complete justice, a justice that avoids the repetition of acts like Acteal," members of Las Abejas not signing the agreement said in a statement. "The justice we long for is to investigate all the authors of the Acteal massacre."