Forty-eight days since their sons were disappeared by police, the parents of the missing 43 Ayotzinapa Normal School students say they will not lose hope their children are still alive, and expressed growing anger at authorities for what they called "psychological torment" over the students' disappearance.

That sentiment fueled more attacks to government-related buildings in Chilpancingo, the capital of Guerrero state. On Wednesday, members of the Guerrero's teachers union and other sympathizers entered the state congress building and set a fire inside the legislative chamber. On Tuesday, at least 500 teachers and others set fire to part of the state headquarters for the Institutional Revolutionary Party (PRI).

Demonstrators set fire to the state congress in Guerrero. Photo by Hans Maximo Musielik.

After protesters set fire to the PRI building, a two-hour-long clash took place between the police and the demonstrators, who armed themselves with rocks, sticks, pipes, and machetes.

Protesters captured deputy public security chief Juan Jose Gatica and held him hostage for two hours, until an exchange could be arranged over the release of two teachers who had been previously detained.

PHOTOS: Protesters angry over the disappearance of 43 students set fires at the Guerrero state congress.— RadicalMedia_ (@UnToldCarlisle)November 12, 2014

Demonstrators in the neighboring state of Michoacan also vandalized the PRI headquarters on Wednesday, as protests spread nationwide after the government last week said the students were likely incinerated at a large dump in the town of Cocula, Guerrero.

_Normalistas _declared to a VICE News reporter that they would set fire to 43 government building in upcoming days to show solidarity with the missing students.

Protestas de normalistas en la sede estatal del— Diógenes (@lamparadiogenes)November 12, 2014

The parents still said they wouldn't lose hope. On Tuesday, they met with the Argentine Forensic Anthropology Team (EAAF), a group entrusted by the government and the families to work alongside state forensics investigators in the search for the young men. The EAAF confirmed that 24 of the 30 bodies that have been found in recent weeks in at least six clandestine graves in Guerrero definitely do not belong to the missing students.

At least 19 clandestine pits with human remains have been uncovered in recent weeks — mostly by volunteers — in the hills surrounding Iguala, the city where the young men went missing after a municipal police attack on buses that left 6 dead. The discoveries have shocked the country and led to massive, mostly peaceful demonstrations in Mexico City and elsewhere.

The experts' statement directly mentions two sites in Iguala where clandestine burial pits were uncovered during the search effort, as well as referring to Cocula, the site of the garbage dump that Mexican investigators presume was used as an incineration site for the corpses of the 43 missing students. Those remains have been sent to experts at the University of Innsbruck in Austria.

The Argentine group's press release concluded the team has "not yet" been able to positively identify any of the remains exhumed during the search effort as belonging to the missing students.

"Until now, there have not been identifications [linking] the remains that were recovered at the three mentioned sites, and the 43 normalistas," the team of Argentine forensics said, further reviving the family members' hopes that their loved ones, who have been missing since September 26, may still be alive.

"We will continue to work on the effort in order to identify the recovered remains, along with the official experts," the statement added.

Charred bone fragments believed to belong to the missing students in Guerrero. Image courtesy of the Mexican Attorney General's Office.

The garbage dump in Cocula, about 14 miles outside Iguala, has become the recent focus of the official investigation.

Attorney General Jesús Murillo Karam on Friday said that according to testimony obtained from three of the suspects who are detained in connection to the case, the _normalistas _were murdered, stacked, and incinerated over the course of 14 hours in Cocula. The suspects said they collected the students' skeletal remains in garbage bags and threw them into a nearby river.

Murillo concluded that due to the degree of incineration, it would be difficult to conduct tests to positively identify the remains.

Murillo Karam's Friday press conference.

"The prosecutor tells the press one thing, and us another," Felipe de la Cruz Sandoval, spokesperson for the families, said in a brief interview with VICE News, after the fifth meeting held between the families and the prosecutor. "He told the media that they were murdered, and then put into graves, or that they were killed and then thrown into a trash dump in Cocula, and then [told] us something else."

"The families react to what they are told," Cruz said. "They cry, they get frustrated, and that is where we disagree, because it's psychological torment. I no longer trust anything they say."

According to Cruz, this final meeting between the parents of the missing and the authorities went two hours longer than scheduled "due to the [parents'] clamoring and criticism of the government, for saying things that are not [true]."

De la Cruz condemned interim Guerrero Governor Rogelio Ortega for his apparent disinterest in the missing students, comparing him to his predecessor Ángel Aguirre, who was forced to resign on October 23. In recent days, Ortega has been criticized for attended a wedding as state buildings in Guerrero burned, and for repeating unverified rumors that the missing Ayotzinapa students were alive.

"He needs to start thinking, or he may have to go out the back door," De la Cruz said.

Ortega criticized protesters' actions after they briefly blocked the international airport in Acapulco, affecting flights in the state's tourist hub. The demonstration, which lasted for about five hours, prompted the governor to say the _normalistas _have become "the bullies, instead of the victims."

Solalinde speaks again

Father Alejandro Solalinde, an outspoken human-rights defender in Mexico, accused the Mexican government of temporarily hiding the former Iguala mayor, Jose Luis Abarca, and potentially using his arrest for political gain. Solalinde was criticized last month for claiming that the Ayotzinapa students were incinerated in Cocula, but the story turned out to be similar to what Murillo Karam said last week about the students' fate.

The mayor and his wife spent several weeks at large before finally being detained at a squalid home in Iztapalapa, an impoverished borough in Mexico City that is considered a major electoral bastion for the Party of the Democratic Revolution (PRD), an opposing force to the PRI.

"They found him in Veracruz and then went to plant him in opposition territory in Mexico City, in Iztapalapa," Father Solalinde claimed on Tuesday.

The Ayotzinapa disappearances have been ricocheting across Mexican society in other ways as well.

The president's step-daughter, actress Sofia Castro, sparked criticism when she declined to comment on the crisis when asked by an entertainment reporter at a red carpet event on Saturday.

"Look sweetheart, this is not the time to talk about the subject," said Castro, Peña Nieto's 21-year-old stepdaughter. "All of Mexico is in mourning. It is shocked by what is happening. But I think that now is not the time, right now I came to have fun and to receive my award."

She wasn't the only one criticized for inappropriate commentary on the missing students case. A tweet from Nestle-owned candy brand Crunch posted a controversial tweet from its official Twitter account in Mexico @CrunchMX, stating "They crunched those from Ayotzinapa." The tweet was removed shortly thereafter, and the company tweeted an apology, claiming their account had been hacked.

Nestlé Crunch's Mexican twitter account made a tasteless joke about the students of Ayotzinapa yesterday. — ?'?Tony_teleSUR? (@MexicAnarchist)November 11, 2014

An official tweet that reads "The Ayotzinapa were given Crunch," presumably in reference to the calcified state of the bones believed to belong to the missing.

In contrast, during an event held this weekend at the New York Museum of Modern of Modern Art, Oscar-winning Mexican director Alfonso Cuarón used his stage time to speak out about the tragedy.

"As Human Rights Watch observes, these killings and forced disappearances reflect a much broader pattern of abuse, and are largely a consequence of the longstanding failure of the Mexican authorities," Cuaron said. "We believe that these crimes are systemic and indicate a much greater evil, the blurred lines between organized crime and high-ranking officials in the Mexican government. We must demand the answers about this and we must do it now."

Pope Francis expressed his condolences Wednesday morning from St. Peter's Square at the Vatican, over what he referred to as the "murder" of the _normalista _students.

"The dramatic reality of all the crime that exists behind drug trafficking becomes evident," the pope said.

Bolivian President Evo Morales is one of few foreign leaders to voice his indignation over the Ayotzinapa case in recent days.

"We regret what has occurred in Mexico, and I decided to express our solidarity," the president said in a statement in Bolivia on Monday.

The seminal Mexican rock band Cafe Tacuba interrupted a concert Tuesday to speak about the missing normalistas, calling what has occurred "a terrible crime of the state."